Respuesta :

mjankiewicz

[tex]\left \{ {{y+2x=3} \atop {y-2x=-1}} \right.[/tex]
[tex]y+y+2x+(-2x)=3+(-1)\\\\ 2y+2x-2x=3-1\\\\ 2y=2 \ |:(-2)\\\\ y=1[/tex]
    ----------
[tex]y+2x=3[/tex]

[tex]1+2x=3 \ |-1\\\\2x=2 \ |:2\\\\ x=1[/tex]
[tex]\left \{ {{x=1} \atop {y=1}} \right.[/tex]


ghanami
hello : 
y+2x=3 ...(1)
y-2x=-1...(2)
by (1) : y =-2x+3
by(2) : y=2x-1
2x-1=-2x+3
2x+2x=3+1
4x=4
x=1
y= 2(1)-1=1