tolong dijawab ya nomor 6 7 dan 8

6. ->1/3x+1/5y=-1
~~~~~~~~~~~~~x15
5x+3y=-15_____ pers1
->1/2x-2/5y=-5
~~~~~~~~~~~~~~x10
5x-10y=-50______pers 2
->5x+3y=-15
5x-10y=-50
------------------- -
13y=35
y=35/13
->5x+3y=-15
5x+3(35/13)=-15
5x+105/13=-15
5x=-15-105/13
5x=-195/13-105/13
5x=-300/13
X=-300/65
X=-60/13
->x-y=-60/13-35/13
=-95/13
7. 4x+5y=2
4x-6y=24
----------------- -
11y=-22
y=-2
->4x+5y=2
4x+5(-2)=2
4x-10=2
4x=12
X=3