Question

If y varies directly with x, find the constant of variation with x = 4 and y = -24

A. -6
B. 4
C. -96
D. 6

I am a little lost on this. Can someone show me how to do this?

Answer 1

use the formula y=kx for this equation.
so considering that Y equals -24 then X and K must also equal that number
we already know that X is -4 but we dont know what K is.
so we divide -24 by -4 and get an answer of a positive 6 but the answer is not proven yet.
-4 times 6 is -24 meaning that the answer is 6

Answer 2

The constant of variation is -6.

A is correct.

Explanation:

If y varies directly with x

`y\propto x`

y is directly proportional to x.

Equation: y=kx

where, k is constant of proportionality or constant of variation.

At x=4 , y=-24

Substitute x and y into equation and solve for k

`-24=4k`

`k=-6`

Hence, The constant of variation is -6.