Question

Diketahui persegi panjang, panjangnya(2x+5)cm dan lebar (4x-10)cm.jika keliling sebenarnya 26cm, panjang dan lebar persegi panjang berturut-turut adalah

Answer 1

Dik :
panajang = 2x +5
lebar = 4x -1 0
K = 26 cm

maka :
K = 2 x (p+l)
26 = 2 x [2x+5 + 4x - 10]
26 = 2 x (6x - 5)
26 = 12x - 10
12x = 26+10
   x   = 3

jadi 
panajang = 2x +5 = 2(3) + 5= 11 cm
lebar = 4x -1 0 = 4(3) - 10 = 2 cm 

Answer 2

L = 2p+2l
26 = 2(2x+5)+2(4x-10)
     = 4x+10+8x-20
     = 4x+8x+10-20
26 = 12x-10
-12x =-26-10
-12x = -36
x = -36/-12 =3

L = 2p+2l
   = 2(2x+5)+2(4x-10)
   = 2(2x3+5)+2(4x3-10)
   = 2(6+5)+2(12-10)
   = 12+10+24+-20
   = 22+4
jadi,p=22cm dan l=4cm