7x=3y+9 2x+5y=12 hasil dari variabel tersebut adalah

Mapel : Matematika
Kelas : VIII SMP
Bab : SPLDV

Pembahasan :
7x = 3y + 9 —» 14x = 6y + 18
2x + 5y = 12 —» 14x + 35y = 84

Eliminasi...
14x + 35y = 84
14x - 6y = 18
———————— (-)
41y = 66
y = 66/41

Substitusi...
7x = 3y + 9
7x = 3(66/41) + 9
7x = 198/41 + 9
7x = 567/41
x = 81/41

Hp : {81/41 , 66/41}

7x = 3y + 9 (kali 2)
14x = 6y + 18

2x + 5y = 12 ( kali 7)
14x + 35y = 84
14x = -35y + 84

14x = 14x
6y + 18 = -35y + 84
6y + 35y = 84 - 18
41y = 66
y = 66/41

2x + 5y = 12
2x + 5(66/41) = 12
2x + 330/41 = 12
2x = 12 - 330/41
2x = 162/41
x = 162 / (41 × 2)
x = 162 / 82
x = 81/41

x = 66/41
y = 81/41

#semoga membantu...
81/41