You'll actually need to graph for the first segment
but the second part can be solved with algebra
The equation of the line is y(x)=-x
if we test the co0ordinates we can find if the point lies on the line
(5,5)
y(x)=-x
Using the x co-ordinate
y(5)= -5
y=-5
Leaving us with (5,-5)
Because (5,-5) is not (5,5)
This is not a point on the line
The slope of the line is -1