Answer:
l = 14
Step-by-step explanation:
The perimeter of a rectangle is
P =2(l+w)
The width is x-6
w = x-6
The length is 8 units longer than the width
l = w+8
l = x-6+8
l = x+2
We can substitute this into the equation for Perimeter, which is given as 40
40 = 2(x+2 + x-6)
Combine like terms
40 =2 (2x-4)
Divide by 2
40/2 = 2/2 (2x-4)
20 = 2x-4
Add 4 to each side
20+4 =2x-4+4
24 = 2x
Divide by 2
24/2 =2x/2
12=x
We want to know the length
l = x+2
l =12+2
l = 14