rolong yang jago matematika nomer 4 bagian a ,b,c.

a) 4x - 5y = - 12
2x + 3y = 16 |×2
4x - 5y = - 12
4x + 6y = 32
---------------------(-)
- 11y = - 44
y = 4
2x + 3y = 16
2x + 3(4) = 16
2x + 12 = 16
2x = 16 - 12
2x = 4
x = 2
hp = {2,4}

b) - 2x + 4y = - 6
3x + 2y = 1 |×2
- 2x + 4y = - 6
6x + 4y = 2
--------------------(-)
- 8x = - 8
x = 1
- 2x + 4y = - 6
- 2(1) + 4y = - 6
- 2 + 4y = - 6
4y = - 6 + 2
4y = - 4
y = - 1
hp = {1,-1}

c) 3x + 4y - 20 = 0
3x + 4y = 20
4x = 3y + 10
4x - 3y = 10

3x + 4y = 20 |×3
4x - 3y = 10 |×4
9x + 12y = 60
16x - 12y = 40
--------------------(+)
25x = 100
x = 4
3x + 4y = 20
3(4) + 4y = 20
12 + 4y = 20
4y = 20 - 12
4y = 8
y = 2
hp = {4,2}