The area of a rectangle is given by:
A = w*h
Where:
w = width = 3(n - 1) = 3n - 3
h = height = n + 2
A = 54 in²
Replacing the data into the equation:
54 = (3n - 3)(n + 2)
Use distributive property on the right hand side:
54 = 3n² + 6n - 3n - 6
Add like terms on the right hand side:
54 = 3n² - 3n - 6
Subtract 54 from both sides:
0 = 3n² - 3n - 60
3n² - 3n - 60 = 0
