Tentukan himpunan penyelesaian sistem persamaan berikut!

#3
a – 2b = 2
a = 2 + 2b

3b – 5a = 4
3b – 5(2 + 2b) = 4
3b – (10 + 10b) = 4
3b – 10 – 10b = 4
3b - 10b = 4 + 10
(-7)b = 14
b = (-2)

a = 2 + 2b
= 2 + (-4)
= (-2)

#8
4c + d = 11
d = 11 – 4c

5c – 2d = 4
5c – 2(11 – 4c) = 4
5c - 22 – 8c = 4
-4 + (-22) = 8c – 5c
-26 = 3c
c = 8,667

d = 11 – 4c
= 11 – 34,667
= -23,667

#9
5g – 2h = 4
15g – 6h = 12
5(4h – 6) – 6h = 12
20h – 30 – 6h = 12
20h – 6h = 12 + 30
14h = 42
h = 3

3g = 4h – 6
= 12 – 6
= 6
g = 2

#10
2r + 3s = 18
2r = 18 – 3s
r = 9 – 3/2s

3(9 – 3/2s) + 2s = 17
27 – 9/2s + 2s = 17
54/2 – 9/2s + 4/2s = 34/2
54 – 9s + 4s = 34
54 – 34 = 9s – 4s
20 = 5s
s = 4

r = 9 – 3/2s
= 9 – 6
= 3