Question

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

A. Y=-3/10 x, 3/10
B. Y=1/10 x,-3/10
C. Y=10/3 x,-10/3
D. Y=-10/3 x, 10/3

Answer 1

Answer:

D

Step-by-step explanation:

Given that y varies directly with x then the equation relating them is

y = kx ← k is the constant of variation

To find k use the condition that y = 10 when x = - 3

k = $\frac{y}{x}$ = $\frac{10}{-3}$ = - $\frac{10}{3}$

y = - $\frac{10}{3}$ x ← equation of variation

When x = - 1, then

y = - $\frac{10}{3}$ × - 1 = $\frac{10}{3}$