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

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### 2 Answers by Expert Tutors

Jennifer J. | Experienced Tutor for GMAT, GRE, LSAT, SAT, and ACT TestsExperienced Tutor for GMAT, GRE, LSAT, S...
4.9 4.9 (65 lesson ratings) (65)
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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!

Thanks!
Vivian L. | Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACHMicrosoft Word/Excel/Outlook, essay comp...
3.0 3.0 (1 lesson ratings) (1)
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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.