Question

(Multiple Choice Worth 4 points)

(07.02)

The following table shows the length and width of two rectangles:


Length Width
Rectangle A 3x + 2 2x - 1
Rectangle B x + 5 5x - 1


Which expression is the result of the perimeter of rectangle B minus the perimeter of rectangle A?
2x + 2
2x + 6
22x + 14
22x + 18

Answer 1

Rectangle A
P = 2l + 2w
P = 2(3x + 2) + 2(2x - 1)
P = 2(3x) + 2(2) + 2(2x) - 2(1)
P = 6x + 4 + 4x - 2
P = 6x + 4x + 4 - 2
P = 10x + 2

Rectangle B
P = 2l + 2w
P = 2(x + 5) + 2(5x - 1)
P = 2(x) + 2(5) + 2(5x) - 2(1)
P = 2x + 10 + 10x - 2
P = 2x + 10x + 10 - 2
P = 12x + 8

Rectangle B - Rectangle A
(12x + 8) - (10x + 2)
12x - 10x + 8 - 2
2x + 6

The correct answer is B.