Neex help with algebra and graphs

Though I did ok with my last assignment on algebra, the stuff applied to graphs is baffling me. It says things like plotting two points to draw the line y=-4x+3 and I just cant get it. I can not seem to put equations and graphs together in my head. There is a graph I am starting at which goes from -5 to 10 on the y axis and - 5 to 10 on the x axis then a line that goes from -5 on the y to 3.5 on the x and asks me to work out the equation for it! I keep going back to the text but just can not get it. Would be so grateful if someone could explain this to me.