il poti rezolva prin doua metode
prima
x+y=3=> x=3-y
2x+3y=5
x=3-y
2(3-y)+3y=5
x=3-y
6-2y+3y=5
x=3-y
6+y=5=> y=5-6
x=3-y
y=-1
x=3-(-1)
y=-1
x=3+1
y=-1
x=4
y=-1
a doua
x+ y=3 /×(-2)
2x+3y=5
-2x-2y=-6
2x+3y=5 (se aduna ecuatiile intre ele)
-2x+2x+(-2y)+3y=-6+5
-2y+3y=-1
y=-1
x+y=3
y=-1
x+(-1)=3
y=-1
x-1=3
y=-1
x=3+1
y=-1
x=4
y=-1
