# The width of a rectangular playground is 2x-5 feet, and the length is 3x + 9 feet. How do you write a polynomial P(x) that represents the perimeter and then evaluate this perimeter and then evaluate this perimeter polynomial if x is 4 feet?

$P \left(x\right) = 2 \left(\left(2 x - 5\right) + \left(3 x + 9\right)\right) = 2 \left(5 x + 4\right) = 10 x + 8$
$P \left(4\right) = 10 \left(4\right) + 8 = 48$
Check. $x = 4$ means a width of $2 \left(4\right) - 5 = 3$ and a length of $3 \left(4\right) + 9 = 21$ so a perimeter of 2(3+21)=48. quad sqrt