Question

Which equations show direct variation between a and b?

Answer 1

Formula of direct variation is: y = kx 
k is the constant of variation
y is the total value that is directly varies with the changes in x.

in this case. x is represented by a. y is represented by b.

A.) b = 0.7a  ⇒DIRECT VARIATION with 0.7 as the constant of variation

B.) b = 1/8 a⁻³  ⇒ Not a direct variation. Because a has a negative exponent

C.) 5(1/a) = b ⇒ Not a direct variation

D.) 1a = b ⇒ DIRECT VARIATION with 1 as the constant of variation