w= width
l= length= w+4
WIDTH
Perimeter= 2(l + w)
substitute l value in equation to find w
40= 2((w+4) + w)
combine like terms in parentheses
40= 2(2w + 4)
multiply 2 by terms in parentheses
40= (2*2w) + (2*4)
multiply in parentheses
40= 4w + 8
subtract 8 from both sides
32= 4w
divide both sides by 4
8 inches= w
LENGTH
substitute w value
l= w + 4
l= 8 + 4
l= 12 inches
ANSWER: Length= 12 inches; Width= 8 inches
Hope this helps! :)
