Thread: How to solve this system of equations problem using the elimination process?

The perimeter of a rectangle is 36 m. If the widths were doubled and the lengths were increased by 11 m, the perimeter would be 70 m. What are the length and width of the rectangle?

Please, not just an answer, but a step by step explanation! :[

2(w + l) = 36
2(2w + l+11) = 70
-------------------------
w+l = 18
2w + l+11 = 35
solving by elimination
2w+l+11 - w - l = 17
w = 17-11 = 6 = width ==> answer
l = 12 = length =======> answer