For a problem like this there is no one solution. It is an inequality. When you graph it you would start with the Y-intercept at (0,10) then you move down 2 on the y axis and move the the right 1 on the x axis as that is your slope. Do that a couple times until you can connect the dots. You will draw a solid line to connect, and shade everything to the left and below the line. Everything in the shaded area are the potential solutions for the inequality.
To your question about (0, -4) that would be in the solution set.
I hope this helps