Answer:
[tex]x = 7[/tex]
[tex]y = - 6[/tex]
Step-by-step explanation:
Add 4y to both sides in the first equation:
[tex]x = 31 + 4y[/tex]
Substitute that new equation into the second equation:
[tex] - (31 + 4y) + 3y = - 25[/tex]
[tex] - 31 - 4y + 3y = - 25[/tex]
[tex] - 31 - y = - 25[/tex]
Add 31 to both sides:
[tex] - y = 6[/tex]
Divide -1 on both sides:
[tex]y = - 6[/tex]
Substitute y=-6 in the third equation (first equation but modified)
[tex]x = 31 + 4y[/tex]
[tex]x = 31 + 4 ( - 6)[/tex]
[tex]x = 31 + ( - 24)[/tex]
[tex]x = 31 - 24[/tex]
[tex]x = 7[/tex]
