If y varies inversely as x, and y = 10 when x = 20,
find x when y = 16.

Answer:

second option

Step-by-step explanation:

Given

[tex]x^{4}[/tex] + 6x² + 5 = 0

let u = x², then

u² + 6u + 5 = 0 ← in standard form

(u + 1)(u + 5) = 0 ← in factored form

Equate each factor to zero and solve for u

u + 1 = 0 ⇒ u = - 1

u + 5 = 0 ⇒ u = - 5

Change u back into terms of x, that is

x² = - 1 ( take the square root of both sides )

x = ± [tex]\sqrt{-1}[/tex] = ± i ( noting that [tex]\sqrt{-1}[/tex] = i ), and

x² = - 5 ( take the square root of both sides )

x = ± [tex]\sqrt{-5}[/tex] = ± [tex]\sqrt{5(-1)}[/tex] = ± [tex]\sqrt{5}[/tex] × [tex]\sqrt{-1}[/tex] = ± i[tex]\sqrt{5}[/tex]

Solutions are x = ± i and x = ± i[tex]\sqrt{5}[/tex]

Answer:

53

Step-by-step explanation:

Explicit Formula: an = a1 + d(n - 1)

Simply plug in your known variables:

an = 8 + 3(n - 1)

Then plug in 16 for n:

a(16) = 8 + 3(16 - 1)

a(16) = 8 + 3(15)

a(16) = 8 + 45

a(16) = 53

Answer:

53

Step-by-step explanation:

an = dn + (a - d)

an = 3n + 8  - 3

an = 3n + 5

Put n as 16 and solve.

3(16) + 5

48 + 5

= 53

Answer:

LJ = CB

Therefore, CJ is 50km

Answer:

3, 6, and 15

Step-by-step explanation:

Notice that if 60 is a multiple, the numbers in question could have the same factors as 60.

So let's look at 60's prime factors:

60 = 2 * 2 * 3 * 5

we also know that 3 is a factor, so the factor 3 must be included in all three options, we also know that 4 is NOT a factor, so both factors 2 cannot be included (but only one of them could).

So, in order to build the lowest possible numbers that verify such conditions, we can use:

3

3 * 2 = 6

since 3 or 2 cannot be repeated, the next smaller would be:

3 * 5 = 15

Answer:

proved

Step-by-step explanation:

prove that : (sin^2 θ)/(1+cosθ)=1-cosθ

(sin^2θ)*(1−cosθ)/(1+cosθ)(1+cosθ) =

sin^2Ф)(1-cosФ)/1-cos^2Ф since 1-cos^2Ф=sin^2Ф then:

(sin^2Ф)(1-cosФ)/sin^2Ф =

1-cosФ     (sin^2Ф/sin^Ф=1)

proved

Answer:

Step-by-step explanation:

take it befor delete

Answer:

B is P(x)=(x-3)^2 +2

C is P(x)=(x-1)^2 -5

Step-by-step explanation:

i think i am right

Answer:

The answer is given below

Step-by-step explanation:

Given that the location of the points are W = (3, 1) , X = (7, -1), Y = (7, -3) and Z = (3,-3)

The distance between two points A(x1, y1) and B(x2, y2) is given by the formula:

[tex]|AB|=\sqrt{(y_2-y_1)^2+(x_2-x_1)^2}[/tex]

Therefore, the side length of the quadrilaterals are:

[tex]|WX|=\sqrt{(-1-1)^2+(7-3)^2}=\sqrt{20} =4.47[/tex]

[tex]|XY|=\sqrt{(-3-(-1))^2+(7-7)^2}=\sqrt{20} =2\\\\|YZ|=\sqrt{(-3-(-3))^2+(3-7)^2}=\sqrt{20} =4\\\\|ZW|=\sqrt{(-3-1)^2+(3-3)^2}=\sqrt{20} =4[/tex]

The Perimeter of the quadrilateral = |WX| + |XY| + |YZ| + |ZX| = 4.47 + 2 + 4 + 4 = 14.47 units

Answer:

4.47,

2

4

14.47

Step-by-step explanation:

Answer:

The population of the city was 25,000 in 1970 and 1983.

Step-by-step explanation:

In order to find the year at which the population was 25,000 we need to make p(t) equal to that number and solve for t as shown below.

[tex]25000 = 14*t^2 + 650*t + 32000\\14*t^2 + 650*t + 7000 = 0\\t^2 + 46.43*t + 500 = 0\\t_{1,2} = \frac{-46.43 \pm \sqrt{(46.43)^2 - 4*1*500}}{2}\\t_{1,2} = \frac{-46.43 \pm \sqrt{155.75}}{2}\\t_{1,2} = \frac{-46.43 \pm 12.48}{2}\\t_1 = \frac{-33.95}{2} = -16.98\\t_2 = \frac{-58.91}{2} =- 29.5[/tex]

Since t = 0 corresponds to the year 2000, then t1 = 1983 and t2 = 1970.

Answer:

804.25 cm² (corrected to 2 decimal places)

Step-by-step explanation:

Radius = diameter / 2

= 16/ 2

=8 cm

Surface area of sphere = 4πr²

= 4π8²

=804.25 cm² (corrected to 2 decimal places)

Answer:

[tex]\displaystyle y = \frac{1}{5}x+1[/tex]

Or:

[tex]x + 5 = 5y[/tex]

Step-by-step explanation:

We have the function:

[tex]y=5x-5[/tex]

And we want to find its inverse.

To find the inverse of a function, we:

Hence:

[tex]x=5y-5[/tex]

Solve for y. Add:

[tex]\displaystyle x + 5 = 5y[/tex]

Divide:

[tex]\displaystyle y = \frac{x+5}{5}[/tex]

Simplify. Hence:

[tex]\displaystyle y = \frac{1}{5}x+1[/tex]

In conclusion, the inverse function is:

[tex]\displaystyle y = \frac{1}{5}x+1[/tex]

Answer:

bearing of A from C is - 65.24°

the distance |BC| is 187.84 m

Step-by-step explanation:

given data

girl walks AB = 285 m (side c)

bearing angle B = 78°

girl walks AC = 307 m (side a)

solution

we use here the Cosine Law for getting side b that is

ac² = ab² + bc² - 2 × ab × cos(B)     ...............1

307² = 285² + x²  - 2 × 285 cos(78)

x = 187.84 m

and

now we get here angle θ , the bearing from A to C get by law of sines

sin (θ) = [tex]\frac{187.84}{307} \times sin(78)[/tex]

sin (θ) =  0.5985  

θ = 36.76°

and as we get here angle BAC that is

angle BCA = 180 - ( 36.76° + 78° )

angle BCA = 65.24°

and here  negative bearing of A from C so - 65.24°

Answer:

Out of 8000 students, 10% take tuition in various subjects before the exam.

10% of 8000 is:

10/100 * 8000 = 800

Among the 800, 40% take tuition in English only and 20% take tuition in Math only.

80 students take tuition in other subjects, therefore, in percentage:

80/800 * 100 = 10%

Therefore, the percentage of students that take tuition in both Math and English is:

100% - (40% + 20% + 10%) = 100% - 70% = 30%

30% of the 800 students take tuition in both subjects. That is:

30/100 * 800 = 240 students

Therefore, among the 8000 students in the district, only 240 take tuition in both English and Math.

In percentage:

240/8000 * 100 = 3%

3% of students take tuition in both English and Math.

In Ratio:

3 : 100

3 out of 100 students take tuition in English and Math.

Step-by-step explanation:

y isn't directly proportional with x because the graph doesn't cross O the origin, it starts from a y-intercept wich is not a property for proportional portions

Answer:

C has the largest area. It is 4.5 square units.

Step-by-step explanation:

A:

area = bh/2 = 2 * 3/2 = 3

B:

area = bh/2 = 2 * 3/2 = 3

C:

area = bh/2 = 3 * 3/2 = 4.5

C has the largest area. It is 4.5 square units.

Answer:

x ≤ -4

Step-by-step explanation:

There is a closed circle at -4, which requires and equals sign

The line goes to the left, which is less than

x ≤ -4

Answer: 12 friends.

Step-by-step explanation:

the data we have is:

Mei Su had 80 coins.

She gave the coins to her friends, in such a way that every friend got a different number of coins, then we have that:

The maximum number of friends that could have coins is when:

friend 1 got 1 coin

friend 2 got 2 coins

friend 3 got 3 coins

friend N got N coins

in such a way that:

(1 + 2 + 3 + ... + N) ≥ 79

I use 79 because "she gave most of the coins", not all.

We want to find the maximum possible N.

Then let's calculate:

1 + 2 + 3 + 4 + 5 = 15

15 + 6 + 7 + 8 + 9 + 10 = 55

now we are close, lets add by one number:

55 + 11 = 66

66 + 12 = 78

now, we can not add more because we will have a number larger than 80.

Then we have N = 12

This means that the maximum number of friends is 12.

Answer:

12

Step-by-step explanation:

my

Answer:

98

Step-by-step explanation:

7x+4 = 88 because they are vertical angles and vertical angles are equal

7x = 88-4

7x = 84

Divide by 7

7x/7 = 84/7

x = 12

<1 and 7x-2 are supplementary angles since they form a line

<1 + 7x-2 = 180

<1 + 7(12) -2 = 180

<1 +84-2 =180

<1 +82 = 180

<1 = 180-82

<1 = 98

Answer-

98

step by step explanation -

7x+4=88

7x=84

x=12

7x-12=7*(12)-2=82

angle 1=180-82 =

Answer:

The times are t = 9, t = 10, t = 11 and t = 12

Step-by-step explanation:

For the train to be more than 16 km South and since south is taken as negative,

d(t) > -16

t³ - 9t² + 6t > -16

t³ - 9t² + 6t + 16 > 0

Since -1 is a factor of 16, inserting t = -1 into the d(t), we have

d(-1) = (-1)³ - 9(-1)² + 6(-1)+ 16 = -1 - 9 - 6 + 16 = -16 + 16 = 0. By the factor theorem, t + 1 is a factor of d(t)

So, d(t)/(t + 1) = (t³ - 9t² + 6t + 16)/(t +1) = t² - 10t + 16

Factorizing  t² - 10t + 16, we have

t² - 2t - 8t + 16

= t(t - 2) - 8(t - 2)

= (t -2)(t - 8)

So t - 2 and t - 8 are factors of d(t)

So (t + 1)(t -2)(t - 8) > 0

when t < -1, example t = -2 ,(t + 1)(t -2)(t - 8) = (-2 + 1)(-2 -2)(-2 - 8) = (-1)(-4)(-10) = -40 < 0

when -1 < t < 2, example t = 0 ,(t + 1)(t -2)(t - 8) = (0 + 1)(0 -2)(0 - 8) = (1)(-2)(-8) = 16 > 0

when 2 < t < 8, example t = 3 ,(t + 1)(t -2)(t - 8) = (3 + 1)(3 -2)(3 - 8) = (4)(1)(-5) = -20 < 0

when t > 8, example t = 9,(t + 1)(t -2)(t - 8) = (9 + 1)(9 -2)(9 - 8) = (10)(7)(1) = 70 > 0

Since t cannot be negative, d(t) is positive in the interval 0 < t < 2 and t > 8

Since t ∈ (0, 12]

In the interval 0 < t < 2 the only value possible for t is t = 1

d(1) = t³ - 9t² + 6t = (1)³ - 9(1)² + 6(1) = 1 - 9 + 6 = -2

Since d(1) < -16 this is invalid

In the interval t > 8 , the only possible values of t are t = 9, t = 10.t = 11 and t = 12.

So,

d(9) = 9³ - 9(9)² + 6(9) = 0 + 54 = 54 km

d(10) = 10³ - 9(10)² + 6(10) = 1000 - 900 + 60 = 100 +60 = 160 km

d(11) = 11³ - 9(11)² + 6(11) = 1331 - 1089 + 66 = 242 + 66 = 308 km

d(12) = 12³ - 9(12)² + 6(12) = 1728 - 1296 + 72 = 432 + 72 = 504 km

Answer:2

Step-by-step explanation:

-5.4+8.2=14/5 and then opposite of -2 3/4 is 2.

Answer:

7. a = 50 degrees

b = 50 degrees

c= 50 degrees

d = 75 degrees

8.

Step-by-step explanation:

7.

a. Vertically opposite angles are equal

b. Vertically opposite angles are equal

c Alternate angles

d. Angles on a straight line.

8. 45 + 45 + 65 + 35 + 40 + 30 = 200m

Hope this helps

Answer:

2+2=4

Step-by-step explanation:

2+2=4

good question like if you have two chocolates and your mom gives you two more than there will be 4 and they will be too delicious

i hope this will help you :)

have a great day

Answer:

2+2=4

Step-by-step explanation:

So you take the 2 numbers 2+2 and you use your finger counting to get to 4. It’s really hard mathematics but you’ll get there. Have a great day!

Answer:

6

Step-by-step explanation:

If 2 of the friends wants to stand beside each other, we can take these 2 friends like 1 option and calculated the number of ways, using the rule of multiplication as:

__ 3_____ * ____2_____ *____1____  =  6

1st place        2nd place        3rd place

Because we have 3 options (2 friends and the friends that are beside each other) for the first place of the picture, 2 options for the second and 1 option for the third.

Step-by-step explanation:

Places A and B are 100 km apart on a highway. One car starts from A and another from B at the same time. If the car travel in the same direction at different speeds, they meet in 5 hours. If they travel towards each other, they meet in 1 hour. What are the speeds of the two cars?

Solution :

Let “x km/hr” be the speed of 1st car

Let “y km/hr” be the speed of the 2nd car

Time = Distance/Speed

Speed of both cars while they are traveling in the same direction = (x – y)

Speed of both cars while they are traveling in the opposite direction = (x + y)

5 = 100/(x -y)

x – y = 100/5

x - y = 20

x - y - 20 = 0 ---(1)

1 = 100/(x + y)

x + y = 100

x + y - 100 = 0--b----(2)

x/(100 + 20) = y/(-20 + 100) = 1/(1 + 1)

x/120 = y/80 = 1/2

x/120 = 1/2 y/80 = 1/2

x = 120/2 y = 80/2

x = 60 y = 40

So, the speed of first car = 60 km/hr

Speed of second car = 40 km/hr

Answer:

Please find attached the required graph and

Step-by-step explanation:

The values for the information given can be written down as follows;

Time, seconds             Volume mL

0,                                    500

12,                                   450

24,                                  400

36,                                  350

48,                                  300

60,                                  250

72 250

84 250

96 250

108 250

120 250

132 250

144 250

156 250

168 250

180 250

192 250

204 250

216 250

228 250

240 250

252 250

264 250

276 250

288 250

300 250

312 225

324,                                        200

336,                                         175

348,                                         150

360,                                         125

372,                                         100

384,                                         75

396,                                        50

408,                                        25

420,                                        0

Answer:

see explanations below.

Step-by-step explanation:

The shown sides are all equal.

If it is a regular polygon, it must have all interior angles equal, and all sides equal.

IF

all sides are equal and all angles are equal,

THEN

it is a regular polygon, with 12 sides, because in regular polygons, all exterior angles are equal, and add up to 360 degrees.

No. of sides = 360/(180-150) = 360/30 = 12 sides.

Answer:

A

Step-by-step explanation:

We know that the y-coordinate has to be 1 so we can eliminate options C and D. If we plug y = 1 into y = -5x + 3 to solve for x we get:

1 = -5x + 3

-2 = -5x

x = 0.4 so the answer is A.

Answer:

option B is the correct option.

Solution,

[tex] {(x - 4)}^{2} = 5 \\ [/tex]

x-4=_+√5

X=4_+√5

Hope this helps...

Good luck on your assignment...

Answer:

(x-4)^2 =5

x^2-16=5

x^2=5+16

x^2=21

√x^2=√21

x=√21

Step-by-step explanation :

First of all open the bracket which has square

Secondly change the position of 16

Note: when a number changes its place , the symbol also changes

then when you get the value take the square root on both sides

and you'll get the answer

Answer:

The answer is

Step-by-step explanation:

To find the graph which shows (f + g)(x) we must first find (f + g)(x)

That's

f(x) = - x² + 3x + 5

g(x) = x² + 2x

To find (f + g)(x) add g(x) to f(x)

That's

(f + g)(x) = -x² + 3x + 5 + x² + 2x

Group like terms

(f + g)(x) = - x² + x² + 3x + 2x + 5

We have (f + g)(x) as

(f + g)(x) = 5x + 5

Since (f + g)(x) is linear the graph which shows (f + g)(x) is the last graph

Hope this helps you

Answer:

last graph or D

Step-by-step explanation:

total number of pages = 550 pages

total amount of time to read the full book = 10 hours

======================================================

Work Shown:

1 hour = 55 pages

4 hours = 220 pages ... multiply both sides by 4

After 4 hours, he had read 220 pages. Since he has 330 still left to read, this brings the total to 220+330 = 550 pages overall

550/55 = 10 hours is the total amount of time needed to read the entire book at a rate of 55 pages per hour. This is assuming the rate is kept constant.

While 10 hours is a lot, it's somewhat plausible to get the full book read in one continuous session. Though he is better off taking (short) breaks every now and then.

Answer:

550 pages

10 hrs

Step-by-step explanation:

he reads 55 pages per hour

4 hrs* 55 pages/hrs=220 pages

the book is 550 pages long

220 pages+330=550 pages

to find the time to read the whole book:

330/55=6 hrs +4 hrs=10

or

550/55=10 hrs