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3 years ago

Variable y varies directly with x2, and y = 96 when x = 4.

1 answer:

4 0

Direct variation is y = kx, where k is the constant of variation.
But now it says y varies directly with x2 (or 2x), so now the x in the equation is 2x.

The equation is y = k(2x)
Now you find k.
y = 96 when x = 4.
(96) = k(2*4)
96 = k(8)
k = 12

The equation is now y = 12(2x)
To find the value of y when x=2, plug 2 into the equation you made. y = 12(2*2) y = 48
_________________
Now it's with a "quadratic variation," which is the same thing except x is squared.
The equation is y = kx^2

But y varies directly with x2 (same thing as 2x), so now it's y = k(2x)^2.

Now you find k by substituting y and x values that were given.
y = 180 when x = 6
(180) = k(2*6)^2
180 = k(12)^2
180 = k(144)
k = 1.25
k, 1.25, is the constant of variation.

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Square has a side length of (x-5). If the perimeter is 24, what is the value of x? *

san4es73 [151]

Answer:

11 units

Step-by-step explanation:

hey there,

< A square has 4 sides that are all always equal to each other. The perimeter is all the sides summed up together. That means (for example), if one side of the square is 2 cm, then we know that the perimeter is 8 cm, because 2 + 2 + 2 + 2 = 8 (or 2×4=8).

Here we are given that one side is equal to "x-5". Pretend that is a number and solve as I did just right above:

(x-5)×4 = 4x -20

Now we know that the perimeter is (4x-20) units (when you don't know what the units are then just put "units").

We also know that the perimeter can be a number which is 24. That means these two values are equal to each other.

4x-20 = 24

Now solve! Bring x to one side, and all the numbers to the other side.

4x = 44

x = 11

We now know that the value of one side of the square (x) is equal to 11 units. >

Hope this helped! Feel free to ask anything else.

6 0

3 years ago

A lil help please T.I.A

ASHA 777 [7]

Answer:

A. x=32 and x=o

YOUR WELCOME

4 0

3 years ago

1. 0 = 2x2 + 17x + 30

Anna11 [10]

Answer:

Simplify the equation and find the value of x

Step-by-step explanation:

$1 = 34 + 17x \\ - 17x = - 1 + 34 \\ 17x = - 33 \\ \\ x = - \frac{33}{17}$

8 0

3 years ago

Read 2 more answers

Which function is the inverse of f(x)= x^3-6x^2+12x-8

Anna71 [15]

We're not given the choices but we don't need them.

The only way this problem is tractable to a middle or high schooler is if the polynomial is perfect cube; a little thought yields

$f(x) = (x-2)^3$

To find the inverse let's call f(x) x and call x y and solve for y.

$x = (y-2)^3$

$y-2 = \sqrt[3]{x}$

$y = 2 + \sqrt[3]{x}$

4 0

3 years ago

Read 2 more answers

How many women must be randomly selected to estimate the mean weight of women in one age group.we want 90% confidence that the s

mojhsa [17]

That is a very good question....

Look Grank

you know that:

confidence interval = mean +or- Margin of Error

and

Margin of Error = (z)*(standard deviation) / (sqrt of n)
where n is the number of sample records

So we need to calculate z-value firstly

It says: "we want 90% confidence"

So that:

confidence90% corresponds to z-value of 1.645

Plug that into our formula of Margin of Error:

Margin of Error = (1.645)*(22) / (sqrt of n)

"The sample mean is within 2.7 lb of the population mean" means that Margin of Error is 2.7

Margin of Error:

2.7 = (1.645)*(22) / (sqrt of n)

Now solve for n:

n=179.66~180

SO that 180 women must be randomly selected to estimate the mean weight of women in one age group.

7 0

3 years ago