okay so when graphing y = 3x - 2 the '3x' is plotted where? and the '2' is plotted where?

Question

i think 2 is on the y axis and then the line goes up three and over one? am i right?

Answer 1

Almost. Notice that when x is zero, then y = -2, not 2. So marking the point (0,-2) is the same as marking -2 on the y-axis. That's why when the line is in the form y=mx+b, the b is called the "y-intercept". In this case, b = -2.

And it's true that m is the slope of the line, which in this case is 3. And slope is "rise over run". So since 3 = 3/1, it follows what you said: up 3, and one to the right. Following that slope from any point brings you to another point on the line. You only need two points to define a line, so once you have the second point, simply "connect the dots" and extend the line.

Answer 2

Yes, you can figure this out additionally by solving for "y". To solve for y, you must set x to 0. When you do this, you see that at x=0, y= -2. The negative is very important to keep track of. The coeffecient of x, in this case your 3, is also the slope of the equation. This is in simple terms, " rise over run". So 3 is also equal to 3/1, which means that the graph "rises 3" and "runs 1" (where rises with positive numbers is up and runs with positive numbers is to the right). I hope this will help you out.

Answer 3

Use sample points to place your line by assigning a value to x and calculating the y value. For example, when x=1, y=1 (3*1 - 2 = 1).