Slope is[tex] \text{m}=\frac{y_1-y_2}{x_1-x_2}=\cfrac{10-2}{1-(-3)} [/tex]
Then you use the equation
[tex]\text{y=mx+b}[/tex]
Where b is the y-intercept. To find it, plug in x and y from one of the points. Say, point 1 (1,10):
[tex]10=m(1)+b[/tex]
You know m (from above) and now you can solve for b.
Rearrange terms:
[tex]y-b=mx[/tex]
And that will be the answer.
Make sense?