Answer:
[tex]x=10\\y=-10\\[/tex]
[tex](10,-10)[/tex]
Step-by-step explanation:
[tex]-y=x[/tex]
[tex]-7x-5y=-20[/tex]
Substitute [tex]-y[/tex] for [tex]x[/tex] in the second equation:
[tex]-7(-y)-5y=-20[/tex]
Multiply:
[tex]7y-5y=-20[/tex]
Combine like terms:
[tex]2y=-20[/tex]
Divide both sides of the equation by the coefficient of [tex]y[/tex], which is [tex]2[/tex]:
[tex]y=-10[/tex]
Now, substitute [tex]-10[/tex] for [tex]y[/tex] in the first equation:
[tex]-(-10)=x[/tex]
Multiply:
[tex]x=10[/tex]
