Find the slopes of each line.
We can use rise/run or m= (x2-x1)/(y2-y1)
But, before going on, the green line is completely straight. A slope is a level of decreasing or increasing value. It is constant, it is the same.
The slope of L3 (green) = 0. (B. m=0)
Let's find the slopes of the other two.
First, blue. Find two points. (3,-2) (5,-1)
m= (-1-(-2))/ (5-3)
m= (-1+2)/(5-3)
m= (1/2) or 0.5
L1= 0.5 (A. m=0.5)
So, It takes a while to find slope- so I won't solve the last one. But, we know that...
L2= C. m= -1.6
I hope this helps!
~kaiker