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Let x be the width, in inches;
then the length is (x+2) inches.
The area is x*(x+2) square inches.
The perimeter is 2x + 2*(x+2) = 4x + 4 inches.
The equation is
x*(x+2) - (4x+4) = 31, or
x^2 +2x - 4x + 2 - 4 = 31
x^2 - 2x - 35 = 0
(x-7)*(x+5) = 0.
Of the two roots x= 7, x= -5, only value of 7 is positive and is the solution to the problem.
The dimensions of the rectangle are 7 and 9 inches. ANSWER
CHECK. The area is 7*9 = 63 sq.inches. The perimeter is 2*(7+9) = 32 inches. The difference is 63 - 32 = 31. ! Correct !
Solved.