Area = length x width
60 = (x+5) (x-2)
60 = x^2 + 3x -10
Subtract 60 from both sides:
x^2 +3x -70 = 0
Solve for x by finding 2 numbers when added together = 3 and when multiplied by each other = -70
x = -10 and 7
Since the sides have to be a positive number we need to use 7
The length = x+5 = 7+5 = 12 cm
The width = x-2 = 7-2 = 5 cm