Answer:
(5/2 , 3/2)
or
(2.5 , 1.5)
(These are the same point; just one is in fraction form and the other in decimal)
Explanation:
I could be wrong but I think you want to solve the system
x+y=4
x-y=1
The cool thing about this system it is already set up for elimination (some people call it linear combination). This means when you add the equations together, a variable will get eliminated allowing you to solve for the other.
x+y=4
x-y=1
----------Add equations.
2x+0=5
2x =5
x =5/2
x =2.5
So plug in your x into either one of the equations and solve for y.
x+y=4
2.5+y=4
y=4-2.5
y=1.5
So the solution is (2.5 , 1.5) or (5/2, 3/2).