A 12 for 8,3,-2 arthimetic sequence

The base of a triangle exceeds the height by 7 centimeters. if the area is 400 square centimeters, find the length of the base and the height of the triangle.

Rewrite the following quadratic functions in intercept or factored form. show your work. y = 5x^2 + 10x

When solving this problem: 3025/5.5 = a/90.75 you get 49912.5 which would be the length of one of the sides of a square when the area is only 90.75 inches. is that answer correct, why, and how is it possible?