Nomor 31 bagaimana caranya? terima kasih

L = p.l
96 = 3x.2x
96 = 6x^2
x^2 = 16
x = 4

k = 2(p+l) = 2(3x + 2x) = 2(5x) = 2(20) = 40

L=p.l
96=3X.2X
96=6X²
X²=96:6
X²=16=4

K=2.(p+l)
=2.(12+8)
=2.(20)
=40 cm