Answer:
L=25; W=17
Step-by-step explanation:
1. Create an equation
L+L+W+W=P -> (2w-9)+(2w-9)+(w)+(w)=84
2. Solve for W
a) Collect like terms
(2w-9)+(2w-9)+(w)+(w)=84 -> 6w-18=84
b) Move constant to the right
6w-18=84 -> 6w=102
c) Divide by 6
6w=102 -> w=17
3. Now plug in W to the L
2w-9=L -> 2(17)-9=L
a) Multiply
2x17=34 -> 34-9=L
b) Subtract
34-9=25 -> 25=L
