Answer:
P=22cm
Step-by-step explanation:
L=8cm
b=(x–5)cm
A=(3x)cm²
we know that:
P=2(l+b)
and that
A=lb= 8(x–5)=8x–40
we have been given the value of A which is 3x, substituting into the equation for Area
=> 3x=8x–40
rearranging
=> x=8
therefore the breadth is (x–5)=(8–5)=3cm
=> P=2(8+3)=2(11)=22cm
hence, the perimeter of the rectangle is 22cm.
