How do you find the b in this: y=2x (For graphing)

Question

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Answer 1

Hi Brenna

 

b is where the line crosses the y axis. You can see this by picking a any number you would like to use for "x." Double it and you have found the y. If you pick x = 0, you will see that y crosses the y axis at )! Cool huh? You can use negative numbers for x, or even x with an exponent and you will never see y crossing the y axis again - only at 0!

 

  

Answer 2

Hi Brenna;

The equation is in the slope-intercept form of...

y=mx+b

m is the slope

b is the y-intercept, the value of y when x=0

y=2x

The fact that b=0 is understood.

y=2x+0

When graphing, the line will cross the y-axis at (0,0).

Furthermore, to establish the x-intercept, the value of x when y=0, set y to 0...

0=2x

0=x

When graphing, the line will cross the x-axis at (0,0).

The slope of this line is 2.  Slope is also known as rise-over-run.  It is the change-of-y divided by the change-of-x.  Begin with the point (0,0), move up (positively y) 2 points and to the right (positively x) 1 point.  Then extend the line.