5/7(12,6-2,8y)=3,6(5/9-3/4y)
5/7(63/5-14/5y)=18/5(5/9-3/4y)
5/7*63/5-5/7*14/5y=18/5*5/9-18/5*3/4y
9-2y=2-2,7y
-2y+2,7y=2-9
0,7y= -7
y= -10
5/7(12,6-2,8y)=3,6(5/9-3/4y)
5/7(63/5-14/5y)=18/5(5/9-3/4y)
5/7*63/5-5/7*14/5y=18/5*5/9-18/5*3/4y
9-2y=2-2,7y
-2y+2,7y=2-9
0,7y= -7
y= -10
9-2y=2-27/10y 90-20y=20-27y
-20y+27y=20-90
7y=-70
y=-10