Question

Tentukan panjang ,lebar,dan luas persegi panjang yg panjangnya (4×-4),lebar (2×+3).jika keliling nya 70luasnya

Answer 1

Keliling = 2p + 2l

2(4x - 4) + 2(2x + 3) = 70
8x - 8 + 4x + 6 = 70
12x - 2 = 70
12x = 70 + 2
12x = 72
x = 72/12
x = 6

panjang = 4x - 4
= 4(6) - 4
= 24 - 4
= 20 cm

lebar = 2x + 3
= 2(6) + 3
=12 + 3
= 15 cm

luas = 20 * 15
= 300 cm²

Answer 2

K = 2(p + l)
70 = 2(4x-4+2x+3)
70 = 2(6x - 1)
70 = 12x - 2
72 = 12x
x = 6

p = 4x-4 = 4(6) - 4 = 20
l = 2x + 3 = 2(6) + 3 = 15

L = p.l = 20.15 = 300cm2