ibu ira membeli 5 kg telur, 2 kg daging, dan 1 kg udang dengan harga Rp.305.000,00. ibu neli membeli 3 kg telir dan 1 kg daging dengan harga Rp.131.000,00. ibu

Pemisalan:telur=x
Daging =y
Udang=z
Dik:5x+2y+z=305000(1)
3x+y =131000 (2)
3y+2z=360000 (3)
Dit : 2x+y+z ?
Jawab : eliminasi pers. (1) dan (2)
5x+2y+z=305000 x 3
3x+y=131000 x 5
15x+6y+3z=915000
15x+5y=655000
y+3z=260000(4)
Eliminasi per. (3) dan (4)
3y+2z=360000x1
y+3z=26000x3
3y+2z=360000
3y+9z=780000
0-7z= -420000
z = -420000 :-7
Z= 60.000
Subst. Pers. (3)
3y+2z=360000
3y + 2(60000)=360000
3y+120000=360000
3y = 360000 - 120000
3y= 240000
Y = 240000 : 3
y = 80000
Subs. Pers. 1
5x+2y+z = 305000
5x+2(80000)+(60000)=305000
5x+160000+60000=305000
5x+220000 = 305000
5x = 305000 - 220000
5x = 85000
x = 85000 : 5
x = 17000
Nilai 2x + y + z =
2(17000)+(80000)+(60000)
34000+140000
= 174000