tolong jawab pertanyaan diatas dengan cara nya plis

1) 3x + y = 11
2x + y = 8
------------------(-)
x = 3
subtitusi
2x + y = 8
2(3) + y = 8
6 + y = 8
y = 8 - 6
y = 2
hp = ( 3,2 ) ( D )

2) 3x + 2y = 12 |×3
4x + 3y = 17 |×2
maka
9x + 6y = 36
8x + 6y = 34
-------------------(-)
x = 2
subtitusi
3x + 2y = 12
3(2) + 2y = 12
6 + 2y = 12
2y = 12 - 6
2y = 6
y = 3
nilai x + y
= 2 + 3
= 5 ( A )

3) 4x - 2y = 2 |×2
5x + 4y = 35
maka
8x - 4y = 4
5x + 4y = 35
------------------(+)
13x = 39
x = 3
subtitusi
4x - 2y = 2
4(3) - 2y = 2
12 - 2y = 2
- 2y = 2 - 12
- 2y = - 10
y = 5
nilai 3x + 2y
= 3(3) + 2(5)
= 9 + 10
= 19 ( D )

4) 5x - 3y = 16 |×4
3x - 4y = 14 |×3
maka
20x - 12y = 64
9x - 12y = 42
--------------------(-)
11x = 22
x = 2
subtitusi
5x - 3y = 16
5(2) - 3y = 16
10 - 3y = 16
- 3y = 16 - 10
- 3y = 6
y = - 2
misal
x = a = 2
y = b = - 2
nilai a.b
= 2 × (-2)
= (-4) ( A )