Which equation describes a line with a slope of 1 and includes the point (1,2)

There are several different forms for the equation of a line. Point-Slope works pretty well for this one.

Remember, point-slope form looks like this: 



Where the _1 means you sub in a point that matches that coordinate.
(x,y)

m, is the slope.

So an equation of the line would look like this: 
(y - 2) = 1(x - 1)

The times 1 slope is implied, so you could also write it as: 
(y - 2) = (x - 1) 

(Removing the parenthesis is also acceptable, in this case)

Let's say you were not given it in point slope form. Then let's take the point slope form we made and put it into the slope intercept form by solving for y.

y -2 = x - 1

Solve for y by adding 2 on both sides. 

y - 2 + 2 = x - 1 + 2 

y = x + 1

Once again the 1 slope is implied. So these are both acceptable forms. I hope this helps!