Im new at this and im still kinda confused.

The parabola y = x² - 4 opens: a.) up b.) down c.) right d.) left

If f(x)=2x-6 and g(x)=3x+9, find (f-g)(x)

Atriangle has an area of 72 square inches. if the base of the triangle has a length of 18 inches, what is the height of the triangle? use the formula for the area of a triangle: area = (base)(height) type a numerical answer in the space provided. do not include the units or spaces in your answer.