a+4b-c=-10 2a-3b+2c=22 4a+b-2c=0 tentukan nilai a,b,c???

soal !

a + 4b - c = - 10
2a - 3b + 2c = 22
4a + b - 2c = 0

jawaban :

2a - 3b + 2c = 22
4a + 6 - 2c = 0
_____________ +
6a - 2b = 22 .......persamaan 4

a + 4b - c = - 10 | × 2 | 2a + 8b - 2c = -20
2a - 3b + 2c = 22 | × 1 | 2a - 3b + 2c = 22
______________ +
4a + 5b = 2..pers. 5

6a - 2b = 22 |×2| 12a - 4b = 44
4a + 5b = 2 |×3| 12a + 15b = 6
___________ -
- 19b = 38
b = - 2
substitusikan b = -2 ke persaman 4

6a - 2b = 22
6a - 2×(-2) = 22
6a + 4 = 22
6a = 22 - 4
a = 18/6
a = 3
substitusikan a = 3 dan b = -2 ke pers 1
a + 4b - c = -10
3 + 4×(-2) - c = -10
3 - 8 - c = -10
-c = -10 + 5
-c = -5
c = 5

jadi nilai a,b,c adalah
a = 3
b = -2
c = 5