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Printjmc
algebra senior
Problem
I have a picture with dimensions and (in inches), such that and are both integers greater than one. I would like to place this picture in an elongated frame of dimensions and . If I measured the area of the frame to be square inches, what is the area of the picture in square inches? (Note that by "the area of the frame," we mean the shaded region shown below). 
Solution
The area of the frame is equal to To apply Simon's Favorite Factoring Trick, we add to both sides of the equation: so Considering the factor pairs of 40, we see that the ordered pair must be among Solving for and for each pair of factors, we find that must be among the pairs Of these, only satisfy the condition that both and are greater than . The area of the picture is thus square inches.
Final answer
8