# Systems Of Equations

## What is a system of equations?

Two or more equations with two or more unknown variables. When graphed, these lines intersect at some point (x, y).Only in "special" cases the equations can be parallel, it's rare but not impossible.

## Graphing

When is graphing most useful?

Graphing is mostly useful when your two equations are already in slope intercept form.

## Substitution

When is substitution most useful?

Substitution is best used when one of your equations is in slope intercept form already, because you can "substitute" the y into your second equation.

Solving by Substitution -Idl9126

## Elimination

When is elimination more useful?

Elimination is best used when your 2 equations are in standard because then all your variables will be lined up.When using elimination you should have at least one pair of variables be opposites , as in positive and negative and you should try to put the variables with the same coefficients.

Solving by Elimination

## Write a system

In order to write a system of equations you have to first find a total , that will always go on the right side of the equals side. Then you want to plug in variables for the parts of your equation. Then you can figure out how you want to solve it , either by elimination,substitution, or graphing.

## Word Problems

Word Problems are pretty much exactly like writing a system but with words. Their the base to writing your system.

## One Solution

This basically when you can only get one solution. So basically if you get an ordered pair that can't be replaced.

## No Solution

This is where the two equations would never intersect so they never have a solution.

## Infinitely many

Pretty self explanatory. Their could be an infinite amount of answers and the lines are usually on top of each other when on a graph.