Question

Is the point (-1, 3) a solution to x + y = 2

Answer 1

If you move x to the other side by subtracting like this:
x-x+y=2-x

y=2-x

Then you plug in those points

3= 2- (-1)

do the math... and the answer is yes.

The ordered pair (-1, 3) is a solution to x+y=2

Answer 2

Yes!
If you substitute the point for the corresponding x and y values, you get -1+3 which does indeed equal 2.