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### Equation for undefined slope

```
Date: 10/24/1999 at 18:43:21
From: Andy
Subject: Equation for undefined slope

How do you write an equation for a vertical line with an undefined
slope?

Example: vertical line with an x-intercept of 8

Sincerely,
Andy
```

```
Date: 10/24/1999 at 22:49:40
From: Doctor Tom
Subject: Re: Equation for undefined slope

x = 8

To avoid the problems of lines that have infinite slopes, don't use
the equation y = mx + b; instead use the equation

ax + by + c = 0

All lines (even with infinite slopes) can be represented using that
equation.

- Doctor Tom, The Math Forum
http://mathforum.org/dr.math/
```
Associated Topics:
High School Basic Algebra
High School Linear Equations
Middle School Algebra
Middle School Equations

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