Slope intercept-form equation:
y=mx+b
Where:
m= slope
b= y-intercept
by looking at the graph we can see that the line crosses the origin (0,0), so it crosses the y-axis at x=0.
b=0
For the slope:
point 1= (x1,y1)= (-2,-4)
Point2= (x2,y2)= (4,8)
Replacing:
So the final expression:
y= 2x