Perimeter is P = 2l + 2w. From the question you know that w = 2l + 5 and that P = 28. To find l, plug the expression for w into the perimeter equation:
28 = 2l + 2(2l + 5)
28 = 2l + 4l + 10
28 = 6l + 10
18 = 6l
3 = l
Now find w by plugging 3 into its equation - w = 2(3) + 5. w = 11
Lastly, check your work by plugging everything back into the perimeter equation: 28 = 2(3) + 2(11), which is 28 = 6 + 22. Correct! So the length is 3 in and the width is 11 in.
