Mr. smith has a square sheet of glass in his garage. he plans to cut 3 inches off of the sheet along the width to use it for a window. the new area of the glass is given by the expression below, where x is the side length, in inches, of the original sheet of glass.

The answer would be: the area removed from the sheet of glass after being cut

Mr. Smith has a square sheet of glass where x is the side length of the original glass. Then, the area of the original glass (before cut) would be: side*side= x^2
He plans to cut 3 inches off of the sheet. The area of the glass that will be cut would be: wide*original glass side= 3*x= 3x 
The area of the sheet of glass after being cut is= x^2 -3x