tolong yang jago matematika nomer 1 bagian c dengan metode eliminasi dan subtitusi

7y + 5x = 6
5x + 7y = 6

y = 2x + 9
- 2x + y = 9
2x - y = - 9

5x + 7y = 6|× 1
2x - y = - 9|× 7

5x + 7y = 6
14x - 7y = - 63
__________+
19x = - 57
x = - 3

2x - y = - 9
- 6 - y = - 9
- y = - 9 + 6
- y = - 3
y = 3

Maaf Kalau Salah

7y + 5x = 6 |x 1| ---> 7y + 5x = 6
y - 2x = 9 |x 7| ---> 7y - 14x = 63
.................................. __________ _
................................ 19x = -57
................................. x = -3

subtitusi x = -3 ke persamaan y = 2x + 9
y = 2x + 9
y = 2(-3) + 9
y = 3

HP : {-3 , 3}