[tex]2c)\\\\ \begin{cases} 0,2(x+2y)-0,3(2x-y)=3,5\ \ |*10\\2(x+y)-(x-2)=2y+2 \end{cases}\\\\\begin{cases} 2(x+2y)- 3(2x-y)=35 \\2 x+2y - x+2 =2y+2 \end{cases}\\\\\begin{cases} 2 x+4y - 6x+3y =35 \\2 x+2y - x -2y=2 -2\end{cases}\\\\ \begin{cases} -4x+7y=35 \\x=0\end{cases}\\\\ \begin{cases}7y=35\ \ |:5 \\x=0\end{cases}\\\\\begin{cases} y=5\\x=0\end{cases}[/tex]
[tex]3b)\\\\ \begin{cases} 3x-y=5\\(x+1)(x+1)-y=x(x+1)\end{cases}\\\\\ \begin{cases}3x-y=5\\x^2+x+x+1-y=x^2+x\end{cases}\\\\\ \begin{cases}3x-y=5\\x^2+x+x-y -x^2-x=-1\end{cases}\\\\\ \begin{cases}3x-y=5\\ x-y =-1\ \ |*(-1)\end{cases}[/tex]
[tex]\begin{cases}3x-y=5\\ -x+y =1\end{cases}\\+ -------- \\2x=6\ \ |:2\\\\x=3\\\\3x-y=5\\ y=3x-5\\y=3*3-5\\y=9-5\\y=4\\\\\begin{cases}x=3\\y=4 \end{cases}[/tex]
