\(\begin{cases} 2x+3y=40 \\ y=x+10 \end{cases}\\\\\begin{cases} 2x+3y=40 \\ -x+ y= 10\ \ / *2 \end{cases}\\\\\begin{cases} 2x+3y=40 \\ -2x+ 2y= 20 \end{cases}\\+-------\\5y=60\ \ / :5\\\\y=12\)
\(\begin{cases} 2x+3y=40 \\ y=x+10 \end{cases}\\\\\begin{cases} 2x+3y=40 \\ -x+ y= 10\ \ / *2 \end{cases}\\\\\begin{cases} 2x+3y=40 \\ -2x+ 2y= 20 \end{cases}\\+-------\\5y=60\ \ / :5\\\\y=12 y=x+10\\12=x+10\\x=12-10\\x=2 \\\\Answer: \ \ \ \begin{cases} x=2 \\ y=12 \end{cases}\)
