diketahui sebuah persegi panjang dengan panjang(2×+1)cm dan lebar (3×-5)cm.jika keliling persegi lanjang 32cm,maka ukuran lebarnya adalah.....cm

2 (p + l) = 32
2 (2x + 1 +3x - 5) = 32
2 (5x - 4) = 32
10x - 8 = 32
10x = 40
x = 4

Lebar
= 3x - 5
= 3(4) - 5
= 12 - 5
= 7 cm

Keliling = 2p + 2l
2p + 2l = 32
2( p + l ) = 32
p + l = 32/2
p + l = 16
(2x + 1) + (3x -5 ) = 16
5x -4 = 16
5x = 16+4
5x = 20
x = 20/5
x = 4
l = 3x -5
l = 3.4 -5
l = 12 - 5
l = 7
Jadi lebar = 7 cm.