A rectangle has a perimeter of 12x + 20 and a width of 2x + 8. What is the length of the rectangle?

3 answers

let the length be l

2l + 2(2x+8) = 12x+20
2l = 8x + 4
l = 4x + 2
how did you get right to.... 2l= 8x + 4 ?
I skipped what I thought was an easy simplification ...

2l + 2(2x+8) = 12x+20
2l + 4x + 16 = 12x + 20
2l = 12x + 20 - 4x - 16
2l = 8x + 4