Question

Mrs. Ishimitsu is installing a rubber bumper around the edge of her coffee table. The dimensions of the rectangular table are (2x2 – 16) feet and (–x2 + 4x + 1) feet. Which expression represents the total perimeter of the table, and if x = 3, what is the length of the entire rubber bumper?

x2 + 4x – 15; 3 feet
x2 + 4x – 15; 6 feet
2x2 + 8x – 30; 6 feet
2x2 + 8x – 30; 12 feet

Answer 1

Perimeter = 2[(2x^2 − 16) + (−x^2 + 4x + 1)] = 2(x^2 + 4x − 15) = 2x^2 + 8x − 30.

If x = 3: perimeter = 2(3)^2 + 8(3) − 30 = 18 + 24 − 30 = 12 feet.

Answer: 2x^2 + 8x − 30; 12 feet.