Answer:
A or the top option
Step-by-step explanation:
I used process of elimination
B simply does not work because in order for 4 to be subtracted by another number to equal 18, that number (width) would have to be negative
C also isn't correct since if it was solved out, we would add four to both sides, making the left side equal to w/2 + 4 which isn't what we want because the length is 4 shorter, not longer
D can be dealt with in the same way, by adding w/2 on both sides, making the left side 4 + w/2, the same as the previous option.