nilai x merupakan penyelesaian dari sistem persamaan linear 3x - y = 12 dan x +4y = 17 adalah...

3x - y = 12 >> ×4
x + 4y = 17 >> ×1
________________
12x - 4y = 48
x + 4y = 17
___________+
13x = 65
x = 65 : 13
x = 5

3x - y = 12
3 × 5 - y = 12
15 - y = 12
-y = 12 - 15
-y = -3
y = 3

x = 5
y = 3
(x, y) = (5, 3)

x + 4y = 17 dikalikan 3
3x - y = 12

3x + 12y = 51
3x - y = 12
Dikurangkan
13y = 39
y = 39/13
= 3 Nilai x : x + 4y = 17 x + 4(3) = 17 x + 12 = 17 x = 17 - 12 = 5