A direct variation function contains the points (2, 14) and (4, 28). Which equation represents the function?

y = y equals StartFraction x Over 14 squared EndFraction.
y = y equals StartFraction x Over 7 squared EndFraction.
y = 7x
y = 14x

Question

A direct variation function contains the points (2, 14) and (4, 28). Which equation represents the function?

y = y equals StartFraction x Over 14 squared EndFraction.
y = y equals StartFraction x Over 7 squared EndFraction.
y = 7x
y = 14x

Mercury · Answer

problem states that it's a direct function (y = kx where k is a constant). we want to find k.

take either of the points (for example, 2,14) and plug them into the equation for x and y. solve for k.

once you have k, plug into the equation y = kx