a. x+2y= -1
4x-2y=6
se aduna cele doua si se reduce 2y cu -2y
ramane: x+4x= -1+6
5x=5
x=5:5
x=1
x+2y= -1
2y= -1-x
2y= -1-1
2y= -2
y= -2:2
y= -1
b) 3x+4y=6
x-4y=-14
la fel se adun si se reduce 4y cu -4y
ramane: 3x+x=6-14
4x= -8
x= -8:4
x= -2
x-4y=-14
x+14=4y
-2+14=4y
4y=12
y=12:4
y=3
