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Question: Show that all line through the points A (p, p +1) and B (2p, p +2) with p ≠ 0 cross the negative x-axis

How do I have to do this?

 Aug 20, 2015

Best Answer 

 #2
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Thanks!

 

 Aug 20, 2015
 #1
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A (p, p +1) and B (2p, p +2)

$$\\gradient=\frac{p+2-p-1}{2p-p}\\\\
gradient=\frac{1}{p}\\\\
y=\frac{x}{p}+b\\\\
Sub\;in\;point\;A\\\\
p+1=\frac{p}{p}+b\\\\
p+1=1+b\\\\
so\;b=p\\\\
$Equation of line is $ y=\frac{x}{p}+p\\\\$$

 

If p is negative the the y intercept is negative and the gradient is negative so it will cut the negative x axis.

If p is positive the the y intercept is positive and the gradient is positive so it will cut the negative x axis.

 Aug 20, 2015
 #2
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+5
Best Answer

Thanks!

 

Guest Aug 20, 2015

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