l= 2.5x + 8
w= 5x - 2.5
Perimeter= 2l + 2w
substitute values above for l and w
P= 2(5x - 2.5) + 2(2.5x + 8)
multiply outer #s by all in parentheses
P=(2*5x) + (2*-2.5) + (2*2.5x) + (2*8)
P=10x - 5 + 5x + 16
combine like terms
P=15x + 11
ANSWER: P= 15x + 11
Hope this helps! :)
