Answer:
The solutions is (8,12).
Step-by-step explanation:
The second equation is solved for x so we can replace the first x in the first equation with what the second x in the second equation equals.
That is we can do this:
x+y=20 where x=-4+y
(-4+y)+y=20
-4+y+y=20
Combine like terms:
-4+2y=20
Add 4 on both sides:
2y=24
Divide both sides by 2:
y=24/2=12
So if x=-4+y and y=12, then x=-4+12=8.
The solution is (8,12).
This means that (8,12) is a common point on both the given equations.
This means it will make both equations true when plugging it in.
x+y=20 with (x,y)=(8,12):
8+12=20 is true since 8+12 is 20.
x=-4+y with (x,y)=(8,12):
8=-4+12 is true since -4+12=8.
