Tolong dijawab semua

1) x - y = 1
x + y = 7
-----------------(-)
- 2y = - 6
y = 3
x + y = 7
x + 3 = 7
x = 7 - 3
x = 4
hp = {4,3}

2) 2x + y = 5 |×2
3x - 2y = 11
4x + 2y = 10
3x - 2y = 11
--------------------(+)
7x = 21
x = 3
2x + y = 5
2(3) + y = 5
y = 5 - 6
y = (-1)
hp = {3,-1}

3) 3x - 5y = - 23 |×2
4x + 2y = 4 |×5
6x - 10y = - 46
20x + 10y = 20
-----------------------(+)
26x = - 26
x = - 1
3x - 5y = - 23
3(-1) - 5y = - 23
- 5y = - 23 + 3
y = - 20 ÷ - 5
y = 4
hp = {-1,4}

4) langsung diubah ke bentuk y = mx + c
2x + 3y = 8 |×3
3x + 2y = 7 |×2
6x + 9y = 24
6x + 4y = 14
----------------------(-)
5y = 10
y = 2
2x + 3y = 8
2x + 3(2) = 8
2x = 8 - 6
x = 2 ÷ 2
x = 1
hp = {1,2}