Harga 5 buah pulpen dan 8 buah pensil adalah....

pulpen = x
pensil = y

6x + 5y = 11.200 --> × 4
8x + 6y = 14.400 --> × 3

24x + 20y = 44.800
24x + 18y = 43.200
---------------------------- -
2y = 1.600
y = 800 --> harga 1 pensil rp800
6x + 5y = 11.200
6x + 5×800 = 11.200
6x = 11.200 - 4.000
6x = 7.200
x = 1.200 --> harga 1 pulpen rp 1.200

harga 5 pulpen & 8 pensil
= 5 × 1.200 + 8 × 800
= 6.000 + 6.400
= Rp12.400

Misi x=pensil
Y=pulpen
=6x+5y=11,200. (×4)
=8x+6y=14,400. (×3)

24x+20y=44,800
24x+18y=43,200 =(-)
2y=1600
Y=800
Substitusi ke persamaan 1
6x+5y=11,200
6x+5(800)=11,200
=6x+4000=11,200
6x=11,200-4000
6x=7200
X=1200
Dit (5x+8y)=.....
=5(800)+8(1200)
=4000+9600
=13,600,00
=B
Thanks