I did a hundred of these problems correctly and then got the incorrect answer for this one. The problem is simply P=2L+2W solve for W.

When I divided both side by 2 I got rid of both the 2's in 2l and 2W so that I ended up with (P/2)-L=W; whereas the actual answer is (P-2L)/2=W.

Apparently when you divide the side of 2L+2W by two you only get rid of the 2 in front of the W and not the two in front of the L. Is this correct?

Can someone explain this to me?

Brucer