Here are a bunch of CORRECT answers, your answer is somewhere in there. For the first CORRECT answer the second point is -5,-9. Don't make the same mistake I did on question 3, but it still shows the correct answer. I love to help.
It's choice two. When you are putting the equation into y=mx+b form you have to subtract the 3x and put it onto the same side as 10. Then you would have 2y=-3x+10 then divide everything by 2 to have y be alone. Then it would be y=-3/2x+5 giving you the slope of the line being -3/2