Direct variations have an equation that looks like y = kx There is NO y intercept, or the y intercept = 0. If you solve for the slope of choices B C and D you get a y intercept that is not 0. For example Take C
4y = 5x + 3 Divide both sides by 4 (the coefficient of y)
4y/4 = 5x/4 + 3/4 Do the division
y = 1.25 x + 0.75.
0.75 is not zero. This is not a direct variation. The same procedure can be done to B and D with the same results and the same comment.
Solution
Your only possible answer is A
The constant of variation =
4y = 12 x Divide by 4
4y/4 = 12x/4 Do the division
y = 3x The coefficient (3) of x is the constant of variation
