Substituție :
-y=7-2x |•(-1)
y=(-7+2x)
y=2x-7
x-2(2x-7)=1
x-4x+14=1
-3x=-13
x=13/3
y=2•13/3 - 7
y=26/3 - 7
y=(26-21)/3
y=5/3
Reducere :
2x-y=7
x-2y=1 |•(-2)
2x-y=7
-2x+4y=-2
________
/ 3y=5 =>y=5/3
2x-y=7 |•(-2)
x-2y=1
-4x+2y=(-14)
x-2y=1
__________
-3x / = -13 =>x=13/3
