12^2 - (9 - 7)^3 + 6 = 12^2 - (?)^3 + 6

Having a hard time understanding this question (see attachment).

Miss henderson wants to build a fence around a rectangular garden in her backyard in the scale drawing the perimeter of the garden is 14 in of the actual length of a b is 20 ft how many feet of fencing what you need

Which equation represents a direct linear variationa. y=x2b. y=2/5xc. y=1/xd. y=x+3