Question

1.hitung himpunan penyelesaian dari 2x+3y=5 & -2x -2y = -10 2.hitung x & y dari 2x -y =5 & x-2y=4
3.hitung x & y dari 3x -5y = 2 & 7x +3y =12
4.selesaikan sistem persamaan linear dengan metode subtitusi. 5x-2y=8 & 3x+2y=8
5.selesaikan sistem persamaan linear dengan metode eliminasi. y-7x+11=0 & 2y+5x-16=0

Answer 1

1) 2x + 3y = 5
-2x - 2y = - 10
---------------------(+)
y = - 5
2x + 3y = 5
2x + 3(-5) = 5
2x = 5 + 15
x = 10

2) 2x-y=5 |×1| 2x - y = 5
x - 2y = 4 |×2| 2x-4y= 8
---------------------------------(-)
3y = - 3
y = - 1
x - 2y = 4
x - 2(-1) = 4
x = 4 - 2 = 2

3) 3x-5y=2 |×7| 21x - 35y=14
7x+3y=12 |×3| 21x + 9y = 36
-----------------------------------(-)
-44y = -22
y = 2
3x - 5y = 2
3x - 5(2) = 2
3x - 10 = 2
3x = 12
x = 4

4) 5x - 2y = 8 --> 2y = 5x-8
3x + 2y = 8
3x + (5x - 8) = 8
3x + 5x = 8 + 8
8x = 16
x = 2
5x - 2y = 8
5(2) - 2y = 8
10 - 2y = 8
-2y = 8 - 10
y = 1

5) y-7x=-11 |×2| 2y-14x=-22
2y + 5x=16|×1| 2y + 5x = 16
---------------------------------(-)
-19x = - 38
x = 2
y = 7x - 11
y = 7(2) - 11 = 3