Can someone show me the steps and process to this problem im about to show x=3 and y=8 what is y2-3x

Uestion 1(multiple choice worth 5 points) (05.02)alex wants to paint one side of his skateboard ramp with glow-in-the-dark paint, but he needs to know how much area he is painting. calculate the area of the isosceles trapezoid. isosceles trapezoid with top base 12 feet, bottom base of 18 feet, and height of 6 feet. 72 ft2 84 ft2 90 ft2 108 ft2