Respuesta :

bcalle
Subtract the two equations.
-y = -7
y = 7
Plug 7 back in to either equation and solve for x.
x + 3(7) = 18
x + 21 = 18
Subtract 21 from both sides
x = -3
(-3,7)
CHECK
-3 + 3(7) = 18
-3 + 4(7) = 25