Respuesta :

klee48
2(x-3)+2(4)=40
2x-6+8=40
2x+2=40
2x=38
x=19
Length=(x-3)=(19-3)=16 cm


apologiabiology
we actually don't need to solve for x, just legnth

P=2(L+W)
40=P
L=x-3=L (since we are solving for Legnth not specifically x)
W=4

40=2(L+4)
divide both sides by 2
20=L+4
minus 4 both sides
16=L

legnth=16 cm (x=19 just fyi)