2x - y= 7 dan x + 2y =1 pake metode subtitusi

[tex]2x - y = 7 \\ y = 2x - 7...(1) \\ subs \: ke \: x + 2y = 1 \\ x + 2(2x - 7) = 1 \\ x + 4x - 14 = 1 \\ 5x = 15 \\ x = \frac{15}{5} \\ x = 3 \\ x = 3 \: subs \: ke \: pers \: (1) \\ y = 2 \times 3 - 7 \\ y = 6 - 7 = - 1[/tex]

2x - y = 7 ....(1)
x + 2y= 1 ...(2)

x + 2y =1
x = 1 -2y .... (3)

masukkan pers (3) ke (1)
2x - y = 7
2(1-2y) - y = 7
2 - 4y - y = 7
2 - 5y = 7
-5y = 7 -2
-5y = 5
y = 5/-5
y = -1

masukkan y = -1 ke pers (3)
x = 1 - 2y
x = 1- 2(-1)
x = 1 +2
x = 3