[tex] \left \{ {{y=-3x-4} \atop {y=2x+1}} \right. \\\\ substitution\ method\\\\
-3x-4=2x+1\ \ \ | subtract\ 2x\\\\
-5x-4=1\ \ \ | add\ 4\\\\
-5x=5\ \ \ | divide\ by\ -5\\\\
x=-1\\\\
y=2x+1=2*(-1)+1=-2+1=-1\\\\
Solution:\\ \left \{ {{y=-1} \atop {x=-1}} \right. [/tex]
