Answer:
(5,-1)
x=5
y= -1
Explanation:
To solve this we're going to solve for one variable in either equation
so we have
x+y=4
We can subtract y and 4 from both sides to get
x-4= -y
Then divide by -1 so that y will be a positive number
-x+4=y
We can plug this in for y in the other equation
2x -2(-x+4)=12
Distribute the -2 and get
2x+2x-8=12
Combine like terms and add 8 to get
4x=20
divide and get x=5
Plug in x=5 into the first equation to get
5+y=4
subtract 5 to get y= -1
Our answer is (5,-1) or x=5 y= -1
I checked this on desmos and the math is correct