Question

How many solutions will this system of equations have?

y = 3.5x - 3.5
y = -3.5x + 3.5

Answer 1

If we sum these 2 equations we will get:
2y = 0   ->   y = 0

Now we replace y=0 in any of 2 equations to solve for x:

0 = 3.5x - 3.5
3.5 = 3.5x
x=1

That means that there is only 1 solution and that one is (1,0)