Mario is constructing a frame for a 10 in .by 8 in. photo. He wants the frame to be the same width all the way around and the total area of the frame and photo to be 120 square inches. What is the dimension of the frame?
Accepted Solution
A:
(10+2x)(8+2x) = 120
4x^2 + 36x + 80 = 120 x^2 + 9x + 20 = 30 --- x^2 + 9x - 10 = 0 ----- (x+10)(x-1) = 0 --- x = 1 inch ---- Ans: Width of frame = 1 in