W= width
L= W+6= length
P= 24 inches
Perimeter= 2(W + L)
substitute L= W+6 for L
24= 2(W +(W+6)
combine like terms in parentheses
24= 2(2W + 6)
multiply 2 by all in parentheses
24= (2*2W) + (2*6)
24= 4W + 12
subtract 12 from both sides
12= 4W
divide both sides by 4
3= W
W= 3 inches
L= W+6= 3+6= 9 inches
CHECK:
24= 2(3 + 9)
24= 2(12)
24= 24
ANSWER:
W= 3 inches
L= 9 inches
Hope this helps! :)