№1476
3)[tex] \left \{ {{x+y=5} \atop {y=-x}} ight. [/tex]
4)[tex] \left \{ {{x-y=5} \atop {3x-3y=15}} ight. ?[/tex]
№1478
2)[tex] \left \{ {{x+y=6} \atop {2x+2y=12}} ight. [/tex]
3)[tex] \left \{ {{x-0.5y=5} \atop {4x-2y=20}} ight. [/tex]