So we know that the perimeter is 40 inches and one of the sides is 7 so logically we do 40-7 to get the length of the three remaining sides combined. Then to find the length q, we have to divide that answer by 3 because the three sides have the same length or (40-7)/3, which simplified is 11, so the length of the side is 11 inches and the expression is q=(40-7)/3.
