To find slope intercept from an order pair we can use (2,6) and (1,3). First you find the slope by doing the equation y2-y1/x2-x1 which in this case will be 3-6/1-2 which turns into -3/-1 which is 3. Then you fill in the equation y-y1=mx(x+x1) which will be y-6=3(x+2) then you can simplify it like this
Step 1. Y-6=3x+6
Step 2. Y=3x+12
I hope this helps