Answer :
Since you said length and width i assume it’s a rectangle not a triangle. Here are the equations:
2L+2W=10
L=2W-7 then 2W=L+7 and plug it in the first equation:
2L+L+7=10
3L=3
L=1
Therefore 2+2W=10
W=4
2L+2W=10
L=2W-7 then 2W=L+7 and plug it in the first equation:
2L+L+7=10
3L=3
L=1
Therefore 2+2W=10
W=4