Write an expression for the amount of money (in dollars) in n nickels

If x = 12 and y = 3, what is the value of x - y 2? 81 6 3 18

The length of a shadow of the building is 36m. the length of the pole, which is perpendicular to the ground, is 1.9m. the length of the pole's shadow is 1.52m. what is the height of the building?

Assume that y varies inversely with x. if y=1.6 when x=0.5 find x when y=3.2