Question 16554: Can you please help me with these two problems. Graph each equation: y=-3x+2. I am having a hard time understanding the x,y charts. Any tips?
And 3x+4y-8=0
Thank You
Answer by rapaljer(4671)   (Show Source):
You can put this solution on YOUR website! When you graph a straight line in the form like y = -3x+2, the easiest way to graph it is to use the y-intercept and the slope. The y-intercept is where the graph crosses the y-axis, which is where x=0, in this case at y=2. Also, the slope of the line is the steepness of the line, which turns out to be the coefficient of x, in this case -3. The slope (the rise over the run), is -3 or -3/1, which means the rise is -3 (down 3) and the run (to the right) is 1. You can use this to graph the line by first marking the y intercept by going up two units on the graph, and putting the first point. Then, with your pencil on that point, go DOWN 3, over (to the right) 1 unit, and put the next point. Connect the points with a line, and the graph should look like this:
For the second graph you have 3x+4y - 8 = 0, which is in standard form. In this case the slope is not obvious, so I think the best way to go is to rewrite the equation as 3x+4y = 8, and graph the TWO easiest points that you have--the X and Y intercepts. First, let x =0 and find y. This means that if x=0, then 4y=8, so y = 2. Next, let y = 0. This means that if y = 0, then 3x=8, so x = 8/3 or about 2.67. Graph these two points by going up 2 on the y axis and putting the first point, then the second point on the x axis between 2 and 3 (doesn't have to be accurate) and draw the line between these two points. It should look like this:
R^2 at SCC
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