Question

for the question -4y=8x, what is the constant of variation?
a. -4
b. -2
c. 1
d. 2

Suppose y varies directly with x, and y=24 when x=8. what is the value of y when x=10?
a. 10
b. 30
c. 80
d. 240
@Ahaanomegas

Answer 1

For the first one, what do you define as the constant of variation? y/x? If so, divide out to get -2. For #2, Note that \[ \frac {y}{x} \] is a constant, and this constant is 24/8 = 3, so the answer is 10*3 = 30.

Answer 2

Solve the first one for y.

Answer 3

The constant of variation is the slope.
Solve the equation for y to get it in the form y = mx + b.
In your case, b = 0. m is the slope.