Graping linear equations

Question

Please Graph

f(x)=x-4

Answer 1

Two points determine a line.    [note: If you want, you may compute others to build your confidence.]

 

With y=f(x)=x-4, the two very easy points to find are:

     (0,-4)    [note: the y-intercept; the place where x=0]

     (4,0)     [note, the x-intercept; the place where y=0]

 

"Connect the dots" and keep on going in each direction!

Answer 2

Chris, this is in slope-intercept form, y = mx + b, where m is the slope and b is the y-intercept.

 

Since there is nothing in front of the x, there is an imaginary 1 there. Mathematicians are lazy, though, and don't like to write anything they don't need to, so we just write 1x as x.

 

Remember also that slope is rise/run, and 1 = 1/1

 

The y-intercept is -4. Put a dot on the y-axis at -4.

 

Since the slope is 1/1, you go up one and right one, both positive, and put a dot there. You can also go down 1 and left 1 from the y-intercept, since -1/-1 = 1, also.

 

Now, draw a line through your 3 points. It should go up and to the right since our slope is positive.