Question

Dik suatu persegi panjang dengan panjang (3xtanbah 5) cm (2x-2) cm .jika keliling persegi panjang tersebut 56cm maka luasnya adalah......cm2

Answer 1

Keliling = 2(p+l)
56 = 2(3x+5+2x+-2)
56 = 2(5x + 3)
56 = 10x + 6
10x = 56-6
10x = 50
x = 50/10
x = 5

p = 3x + 5 = 3(5) + 5 = 15 + 5 = 20 cm
l = 2x - 2 = 2(5) - 2 = 10 - 2 = 8 cm

luas = p x l
luas = 20 cm x 8 cm
luas = 160 cm²

Answer 2

56 = 2(3x+5) + 2(2x-2)
56 = 6x + 10 + 4x - 4
56 - 10 + 4 = 6x + 4x
50 = 10x
50/10 = x
5 = x

Panjang = 3.5+5 = 20 cm
Lebar = 2.5-2 = 8

L = 20 × 8
L = 160

maaf kalo salah:)