28.
[tex]2x+1=-3x+2 /+3x\\2x+3x+1=2 /-1\\5x=2-1\\5x=1 /:5\\x=\frac15[/tex]
[tex]y=2*\frac15+1\\y=\frac25+1\\y=\frac25+\frac55\\y=\frac75[/tex]
28.2
[tex]\left \{ {{y=2x+4} \atop {y=-x+1 /*2}} \right. \\+\left \{ {{y=2x+4} \atop {2y=-2x+2}} \right. \\y+2y=4+2\\3y=6 /:3\\y=2\\2=-x+1 /-1\\1=-x\\-1=x[/tex]
