Answer:
a. 1.5 inches wide.
Explanation:
If the width of the frame is x the length of the picture + frame = 2x + 12 and the width is 2x + 9 , so we have the following equation:
The total area = (2x + 9)(2x + 12) = 180
4x^2 + 24x + 18x + 108 = 180
4x^2 + 42x - 72 = 0
2(2x^2 + 21x - 36) = 0
2 (2x - 3 )(x + 12) = 0
x = 1.5 , -12 (we ignore the negative root).