Suppose y varies directly with x, and y = 10 when x = –3. What direct variation equation relates x and y? What is the value of y when x = –1?

Question

jadeishere · Answer

what is the difference between 10 and -3? -13 so -1 + 13 = 12

whpalmer4 · Answer

@Jadeishere No, that's not how these problems work.

Direct variation between $x$ and $y$ means that $$y = kx$$ where $k$ is the constant of variation.

Use your initial values of $x$ and $y$ in that formula to find the value of $k$.  Then replace $k$ in $y = kx$ with the value you found, and put in the value $x = -1$ to find the value of $y$ when $x=-1$.

jadeishere · Answer

Okay, fine