What is x+y=2 cause I don't know the answer

Well, you probably want this equation in line form which is y = mx + b where m is the slope and b is the y-intercept (where the line runs into the y axis):

x + y = 2

y = - x + 2

↑ ↑

slope y-intercept

This line will look like y = x which is a positive line at a 45 ° angle and passes through the origin (0, 0). However, it is going to slope downward since the slope is negative, and the line is moved upward a bit to cross through the y axis at 2.

Obviously the answer is x equals 1 and y equals one so that's how it comes out to be 2