Question

If y varies directly with x and y = 21 when x = 3, find y if x = 5.

First, find the direct variation equation. y = [ ? ] x​

Answer 1

when y = 21, x = 3

when y and x vary directly, that means there is something that you multipy x that gets you to y.

to solve for this number, you divide y by x.

21= 3=7

this means to go from x to y, you multiply x by 7.

7x = y

we can use this to solve for x when y = 42

7x = 42

divide both sides by 7

X = 6

when y = 42, x = 6