Answer :
These are the equations:
2L+2W=58
L=W+5
Now plug in the second one in the first one:
2(W+5)+2W=58
4W+10=58
4W=48
W=12
L=17
2L+2W=58
L=W+5
Now plug in the second one in the first one:
2(W+5)+2W=58
4W+10=58
4W=48
W=12
L=17