The formula of a perimeter of a rectangle:
P = 2(l + w)
We have P = 34 and l = 2w - 4.
Substitute:
2(2w - 4 + w) = 34
2(3w - 4) = 34 use distributive property
(2)(3w) + (2)(-4) = 34
6w - 8 = 34 add 8 to both sides
6w = 42 divide both sides by 6
w = 7
l = 2w - 4 → l = 2(7) - 4 = 14 - 4 = 10
Answer: the length = 10 and the width = 7.
