You can use the slope-intercept form of the equation of a line.
[tex] y = mx + b [/tex]
m is the slope. We are told m = 2.
Now we have
[tex] y = 2x + b [/tex]
We need to find b, the y-intercept. We are given a point, (2, 0). We replace x with 2 and y with 0. Then we solve for b.
[tex] 0 = 2(2) + b [/tex]
[tex] -4 = b [/tex]
Now that we know that b = -4, we replace b with -4.
[tex] y = 2x - 4 [/tex]