Question

1. 2y - x = -2 dan x + y = 7. tentukan metode substitusi dan campuran
2. 3x + 2y = 6 dan x - y = 1. tentukan metode substitusi dan campuran
3. x - y = 3 dan x - 3y = -4 . tentkan substitusi dan campuran
4. 5x + y = 5 dan 17x + y = -5 . tentukan substitusi dan campuran

5. -9 < 3x < 18. tentukan pertidaksamaan

Answer 1

1) 2y-x = -2
y+x = 7
-------------- +
3y = 5
y = 5/3

x+y = 7
x+5/3 = 7
x = 7-5/3
x = 21/3-5/3
x = 16/3

2) 3x+2y = 6 >>x1
x-y = 1 >>x2

3x+2y = 6
2x-2y = 2
----------- +
5x = 8
x = 8/5

x-y = 1
8/5-y = 1
-y = 1-8/5
-y = 5/5-8/5
y = 3/5

3) x-y = 3
x-3y = -4
----------- -
2y = 7
y = 7/2

x-y = 3
x-7/2 = 3
x = 3+7/2
x = 6/2+7/2
x = 13/2

4) 5x+y = 5
17x+y = -5
------------ -
-12x = 10
x = - 10/12

5x+y = 5
5(-10/12)+y = 5
-50/12+y = 5
y = 5+50/12
y = 60/12+50/12
y = 110/12

5) -9>3x<18 >> :3
-3>x>6