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From the condition, the height of the box is 4 inches;
therefore, the area of its base is = 36 square inches.
If w is the width of the original cardboard in inches, then its length is (w+9) inches.
The dimensions of the base of the box are then (w-2*4) = (w-8) inches and (w+9-2*4) = (w+1) inches.
So you have this equation for the base area
(w-8)*(w+1) = 36.
Simplify and solve
w^2 - 8w + w - 8 = 36
w^2 - 7w - 44 = 0.
= = = .
Only positive root w = = 11 makes sense.
ANSWER. The original cardboard dimensions are 11 inches and 20 inches.
Solved.