How to Find the Equation of a Line
Know what to look for., Identify the type of problem., Attack the problem using one of the four methods below.
Step-by-Step Guide
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Step 1: Know what to look for.
Before you can find the equation, make sure you have a clear idea of what you're trying to find.
Pay attention to these words:
Points are identified with ordered pairs such as (-7,
-8) or (-2,-6).
The first number in an ordered pair is the x-coordinate.
It controls the point's horizontal position (how much to the right or left of the origin).
The second number in an ordered pair is the y-coordinate.
It controls the point's vertical position (how much up or down from the origin).
The slope between two points is defined as "rise over run" — in other words, the description of how far you must travel up (or down) and to the right (or left) in order to move from one point to the other.
Two lines are parallel if they do not intersect (cross over each other).
Two lines are perpendicular if they intersect to form a right angle (90 degrees). -
Step 2: Identify the type of problem.
You are given a point and a slope.
You are given two points but no slope.
You are given a point and another line that is parallel to yours.
You are given a point and another line that is perpendicular to yours. , Depending on what information you're given, there are different ways to solve it. -
Step 3: Attack the problem using one of the four methods below.
Detailed Guide
Before you can find the equation, make sure you have a clear idea of what you're trying to find.
Pay attention to these words:
Points are identified with ordered pairs such as (-7,
-8) or (-2,-6).
The first number in an ordered pair is the x-coordinate.
It controls the point's horizontal position (how much to the right or left of the origin).
The second number in an ordered pair is the y-coordinate.
It controls the point's vertical position (how much up or down from the origin).
The slope between two points is defined as "rise over run" — in other words, the description of how far you must travel up (or down) and to the right (or left) in order to move from one point to the other.
Two lines are parallel if they do not intersect (cross over each other).
Two lines are perpendicular if they intersect to form a right angle (90 degrees).
You are given a point and a slope.
You are given two points but no slope.
You are given a point and another line that is parallel to yours.
You are given a point and another line that is perpendicular to yours. , Depending on what information you're given, there are different ways to solve it.
About the Author
Robert Kelly
A passionate writer with expertise in hobbies topics. Loves sharing practical knowledge.
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