3 Title

Beginning Algebra
Tutorial 21: Graphing Linear Equations

 Answer/Discussion to 1a y = 2x - 1

 If we subtract 2x from both sides, then we can write the given equation as -2x + y = -1.  Since we can write it in the standard form, Ax + By = C, then we have a linear equation.  (return to problem 1a)

 If we add x squared to both sides we would end up with .   Is this a linear equation?  Note how we have an x squared as opposed to x to the one power.  It looks like we cannot write it in the form Ax + By = C, because the x has to be to the one power, not squared.  So this is not a linear equation.  (return to problem 1b)

 Answer/Discussion to 2a  y = 2x - 1

The three x values I'm going to use are -1, 0, and 1.  (Note that you can pick ANY three x values that you want.  You do not have to use the values that I picked.) You want to keep it as simple as possible.  The following is the chart I ended up with after plugging in the values I mentioned for x.

 x y = 2x - 1 (x, y) -1 y = 2(-1) - 1 = -3 (-1, -3) 0 y = 2(0) - 1 = -1 (0, -1) 1 y = 2(1) - 1 = 1 (1, 1)

The three x values I'm going to use are -1, 0, and 1.  (Note that you can pick ANY three x values that you want.  You do not have to use the values that I picked.) You want to keep it as simple as possible.  The following is the chart I ended up with after plugging in the values I mentioned for x.

 x y = -1/2x (x, y) -1 y = -1/2(-1) = 1/2 (-1, 1/2) 0 y = -1/2(0) = 0 (0, 0) 1 y = -1/2(1) = -1/2 (1, -1/2)

Last revised on July 29, 2011 by Kim Seward.