Brenda and Joe are retired and are the proud grandparents of

Brenda and Joe are retired and are the proud grandparents of five grandchildren. Brenda enjoys quilting, and plans to make a blanket for her youngest grandchild. The blanket will be 72 inches long and 48 inches wide. Brenda wants to leave a border x inches wide along the perimeter of the blanket. See the following picture. What is the expression that represents the green area located inside the border? If the expression is written in the format ax^2+bx+c. what are the values of a,b, c?

Solution

After Brenda leaves a border x inches wide along the perimeter, the banket , if we leave out the border, would admeasure 72- 2x inches by by 48 -2x inches. The area og the remaining portion of the blanket is (72 - 2x) * (48 - 2x) = 3456 - 96x - 144x + 4x² = 4x² -240x + 3456. Thus a = 4 , b = -240 and c = 3456.

NOTE: The picture has not been uploaded. However, the border being of uniform width x , the measurement of the blanket less the border ( the area located inside the border) will be as above.