Question 362124
L=W+28      
2L+2W=140
2(W+28)+2W=140    
2W+56+2W=140 
4W=140-56
4W=84
W=84/4
W=21 ANS. FOR THE WIDTH.    
L=21+28=49 ANS. FOR THE LENGTH.
PROOF: 
2*49+2*21=140
98+42=140                
140=140