Question

Nilai (x,y) yang memenuhi sistem persamaan
2x+y=5
X+2y=7

Answer 1

2x + y = 5 maka y=5-2x
x+2y = 7
x+2(5-2x) = 7
x+10-4x=7
-3x = 7-10
x=1 maka y=5-2=3

Answer 2

2x + y = 5 |× 1 | 2x + y = 5
x + 2y= 7 |× 2| 2x + 4y = 14
------------------ -
-3y=-9
y= -9/-3 = 3
substitusikan
2x + y = 5
2x + 3 = 5
2x = 5 - 3
2x = 2
x = 2/2 = 1
maka (x,y) = (1,3)