1)

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

Далее смотри во вложении

2)

[tex]\displaystyle\\\left \{ {{3x+y=4} \atop {5x-2y=14}} \right. \\\\\left \{ {{y=4-3x} \atop {5x-2y=14}} \right.\\ \\5x-2(4-3x)=14\\5x-8+6x=14\\11x=22\\x=2= > y=4-3\times2=-2[/tex]