To find the solution, we use the substitution method.
x+y=-1
x-3y=11
x+y = -1-y
-y
x = -1-y
Now apply the value of x into the other equation.
x-3y=11
-1-y-3y = 11
Combine like terms
-4y -1 = 11
+1 +1
-4y = 12
-4y = 12
-4y/-4 = 12/-4
y = -3
Now, apply the value of Y to one equation to find x.
y = -3
x -3 = -1
+3 +3
x= 2
Now we have the value for both, x and y.
x = 2
y =-3
Final answer: A. (2, −3)
