Bentuk Subtitusi : 1. X + Y =1 X + 5Y =5 2. 3X + 2Y =12 2X - Y =8 3. 2X + Y =5 3X - 2Y =4 4. 3X + 2Y =12 2X +3Y =18 Pakai Cara!

1. x + y = 1 => x = 1 - y disubstitusikan ke
x + 5y = 5
(1 - y) + 5y = 5
5y - y = 5 - 1
4y = 4
y = 1

y = 1 disubstitusikan ke x + y = 1
x + 1 = 1
x = 1 - 1
x = 0

2. 2x - y = 8
2x - 8 = y disubstitusikan ke 3x + 2y = 12

3x + 2y = 12
3x + 2(2x-8) = 12
3x + 4x -16 = 12
7x = 12 + 16
x = 28 : 7
x = 4

x = 4 disubstitusikan ke 2x - y = 8
2(4) - y = 8
8 - y = 8
8 - 8 = y
0 = y
y = 0

3. 2x + y = 5
y = 5 - 2x disubstitusikan ke
3x - 2y = 4
3x - 2(5 - 2x) = 4
3x - 10 + 4x = 4
3x + 4x = 4 + 10
7x = 14
x = 14 : 7
x = 2

x = 2 disubstitusikan ke 2x + y = 5
2.2 + y = 5
4 + y = 5
y = 5 - 4
y = 1

4. 3x + 2y = 12
2y = 12 - 3x
y = 6 - 3/2x disubstitusikan ke
2x + 3y = 18
2x + 3(6 - 3/2x) = 18
2x + 18 - 9/2x = 18
2x - 9/2x = 18 - 18
samakan penyebut
4/2x - 9/2x = 0
-5/2x = 0
x = 0. -2/5
x = 0

x = 0 disubstitusikan ke 3x + 2y = 12
3.0 + 2y = 12
2y = 12
y = 12 : 2
y = 6