tolong di bantu soalnya saya belum paham

2x - 5y = 10 |×2
3x - 2y = - 7 |×5
maka
4x - 10y = 20
15x - 10y = - 35
-----------------------(-)
- 11x = 55
x = - 5
disubtitusi ke pers :
2x - 5y = 10
2(-5) - 5y = 10
- 10 - 5y = 10
- 5y = 10 + 10
- 5y = 20
y = - 4
hp = { - 5 , - 4 } ( A )