tentukan himpunan penyelesaian dari sistem persamaan linear berikut menggunakan metode sunstitusi 1. x=y+4 2x+3y=13 2. 4y=-5x 5x+8y=20 3. 2x+3y=-5 x-3y=2 4. 2x-

1) x = y + 4
disubtitusi ke pers :
2x + 3y = 13
2(y + 4) + 3y = 13
2y + 8 + 3y = 13
5y = 13 - 8
5y = 5
y = 1
disubtitusi ke pers :
x = y + 4
x = 1 + 4
x = 5
hp = ( 5, 1 )

2) 4y = - 5x
disubtitusi ke pers :
5x + 8y = 20
5x + (2 • 2y) = 20
5x + 2(-5x ) = 20
5x - 10x = 20
- 5x = 20
x = - 4
disubtitusi ke pers :
4y = - 5x
4y = - 5 ( - 4 )
4y = 20
y = 5
hp = ( - 4,5 )

3) x - 3y = 2
x = 3y + 2
disubtitusikan ke pers
2x + 3y = - 5
2(3y + 2) + 3y = - 5
6y + 4 + 3y = - 5
9y = - 5 - 4
y = - 9 ÷ 9
y = - 1
disubtitusi ke pers :
x = 3y + 2
x = 3(-1) + 2
x = - 3 + 2
x = - 1
hp = ( - 1 , - 1 )

4) 2x - 7y = 17
2x = 7y + 17
disubtitusi ke pers
4x - 5y = 25
( 2 • 2x ) - 5y = 25
2(7y + 17 ) - 5y = 25
14y + 34 - 5y = 25
9y = 25 - 34
9y = - 9
y = - 1
disubtitusi ke pers
2x = 7y + 17
2x = 7(-1) + 17
2x = - 7 + 17
2x = 10
x = 5
hp = ( 5 , - 1 )