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### Linear equation

In analytic geometry, a **linear equation** can always be expressed as an equation of the first degree in two unknowns

ax + by + c= 0

and forms a straight line.

##### Explanation

At school you learn that the equation of a straight line is written as

y=ax+b

or as

y=mx+n

but of course that is all the same. After all, you can also write the linear equation as

by=−ax −c

from which follows

In mathematics use the notation that fits best in a particular case. It is not a question of what is beautiful or what you usually do, but for what is clear.