Answer: x = 5; y = -5
[tex]\left \{ {{-7x-3y=-20} \atop {3x+6y=-15}} \right. \\\\<=>\left \{ {{-7x-3y=-20} \atop {x+2y=-5}} \right. \\\\<=>\left \{ {{-7(-5-2y)-3y=-20} \atop {x=-5-2y}} \right. \\\\<=>\left \{ {{35+14y-3y=-20} \atop {x=-5-2y}} \right. \\\\<=>\left \{ {{11y=-55} \atop {x=-5-2y}} \right. \\\\<=>\left \{ {{y=-5} \atop {x=5}} \right.[/tex]
Step-by-step explanation:
