SOLUTION: how would I graph the line with a slope of 3 and passes through points (2,1) and (4,7).

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Question 115649: how would I graph the line with a slope of 3 and passes through points (2,1) and (4,7).
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
If you only want to graph the line, simply plot the two points (2,1) and (4,7) and draw a straight line through them.



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However, if you want to find the equation of the line, then...

First lets find the slope through the points (,) and (,)

Start with the slope formula (note: is the first point (,) and is the second point (,))

Plug in ,,, (these are the coordinates of given points)

Subtract the terms in the numerator to get . Subtract the terms in the denominator to get


Reduce

So the slope is


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Now let's use the point-slope formula to find the equation of the line:



------Point-Slope Formula------
where is the slope, and is one of the given points

So lets use the Point-Slope Formula to find the equation of the line

Plug in , , and (these values are given)


Distribute

Multiply and to get

Add to both sides to isolate y

Combine like terms and to get
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Answer:


So the equation of the line which goes through the points (,) and (,) is:

The equation is now in form (which is slope-intercept form) where the slope is and the y-intercept is

Notice if we graph the equation and plot the points (,) and (,), we get this: (note: if you need help with graphing, check out this solver)

Graph of through the points (,) and (,)

Notice how the two points lie on the line. This graphically verifies our answer.

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