Explanation
Let's denote the original length and width of the rectangle as L and W, respectively.
The original perimeter is:
2L + 2W = 34
If we increase the length by 2 cm, the new perimeter will be:
2(L + 2) + 2W
= 2L + 4 + 2W
The difference in perimeter is:
(2L + 4 + 2W) - (2L + 2W)
= 4