Ответы и объяснения

2013-11-21T17:21:51+04:00
2(x+y)-7(x+y)+3=0
2x-3y=-1

-5(x+y)+3=0
2x-3y=-1

-(5x+5y)+3=0
2x-3y=-1

-5x-5y+3=0
2x-3y=-1

-5x-5y=-3
2x-3y=-1

(-5x-5y)(-3)=(-3)(-3)
(2x-3y)5=-1

-(-5x-5y)*3=3*3
2x-3y=-1