2a+4b=16 6a+2c=20 3b-2c=1 nilai dari a+3b-5c mohon di bantu

6a + 2c = 20
3b - 2c = 1
__________ +
6a + 3b = 21 ... (1)

2a + 4b = 16 | 3 | 6a + 12b = 48
6a + 3b = 21 | 1 | 6a + 3b = 21
__________ -
9b = 27
b = 3
2a + 4b = 16
2a + 4(3) = 16
2a + 12 = 16
2a = 4
a = 2

3b - 2c = 1
3(3) - 2c = 1
9 - 2c = 1
-2c = -8
c = 4

nilai dari
a + 3b - 5c
= 2 + 3(3) - 5(4)
= 2 + 9 - 20
= -9