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Using the Slope-Intercept Formula

Date: 9/27/95 at 22:30:28
From: Andy Plotkin
Subject: Algebra II Honors High School

Is  y = 11x + 6  and  y - 7 = 11(x - 3)  the same thing?

"Has x- intercept of 5 and slope of -2/3"    How would I 
write an equation for the line described?

Thank You, 
Wendy Plotkin

Date: 9/27/95 at 22:45:28
From: Doctor Andrew
Subject: Re: Algebra II Honors High School

If you can find two different points (x,y) that satisfy both 
equations you've got the same line, since two points uniquely 
define a line.  You could also show that they are 
algebraically equivalent by solving each one for zero (0 = ab 
+ by + c), setting the non-zero sides equal to each other
and seeing if you can get 0 = 0.

>"Has x- intercept of 5 and slope of -2/3"    How would I 
>write an equation for the line described?

The slope/intercept form of the equation for a line is:

y = mx + b where m is the slope and b is a Y-intercept.

However, you don't know the y-intercept, you know the x-
intercept.  The x-intercept is the value of x such that 
y = 0.  So if you plug in the slope into m, the x-intercept 
value into x, and let y = 0, you can solve for b, the 

Hope this helps.  Good luck!

-Doctor Andrew,  The Geometry Forum

Associated Topics:
High School Basic Algebra

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