2a-3b=2 4a+5c=5 6b-10c=-3

4a-6b =4
4a+5c=5
--------------- -
-6b-5c=-1

-6b-5c=1
6b-10c=-3
---------------- +
-15c=-2
c=2/15

4a+5x2/15=5
4a+6=5
a=-1/4

2x-1/4-3b=2
-3b=2+1/2
-3b=5/2
b= -5/6