So for 4, first thing you need is slope. Choose 2 points. I am choosing (8,2) and (6,3) So, then its the second y term subtracted by the first y term over(Or divided by) the second x term subtracted by the first x term.
3-2/6-8 or 1/-2 or -.5 (negative 0.5)
Now, time to find the yintercept(yint). So, choose one of the points, Im choosing (8,2), and put it into slope intercept, but leave yint as b.
(2)=-.5(8)+b
simplify
2= -4+b
subtract -4
b=6
So, your answer is y= -0.5x+6
I will right number 6 in anoher answer