You first used pemdas so that will be 6x times -2 it should be -18
Google “slope calculator” on google
Use calculator soup.
Slope is

Then you use the equation

Where b is the y-intercept. To find it, plug in x and y from one of the points. Say, point 1 (1,10):

You know m (from above) and now you can solve for b.
Rearrange terms:

And that will be the answer.
Make sense?