# Specify Equations in Graphing Question Answer Keys

When you use `line`, `circle`, `parabola`, or `region` in your graphing question answer key, you have the option of specifying an equation for the key. You can use the following notation in your equations.

Note:

- Do not use commas or spaces to separate digits in numbers. For example, 1000000 is correct, but 1,000,000 and 1 000 000 are not.
- Do not use mixed numbers. Instead, use improper fractions. For example, 7/4 is correct, but 1 3/4 is not correct.

Expression |
Notation |
Examples |
---|---|---|

Math variables |
The only allowed variables in graphing question answer keys are |
line: y=x+1 |

Addition |
+ |
line: y=x+1 |

Subtraction |
- |
line: y=x-1 |

Multiplication |
* You must use explicit multiplication. |
line: y=x*2 |

Division or fractions |
/ |
line: y=x/4 |

Exponentiation |
^ Ensure that your equation specifies a linear, circular, or parabolic function. |
parabola: y=x^2 circle:(x-1)^2+(y+3)^2=25 |

Equality |
= |
line: y=x+1 |

Inequality |
> < >= <= |
region: y>x+1 region: y<x+1 region: y>=x^2+3*x+1 region: (x-1)^2+(y+3)^2<=25 |

Order of Operations |
() |
circle:(x-1)^2+(y+3)^2=25 |

Pi (π) |
pi Substituting 3.14 only approximates this value. |
parabola: y=pi*x^2 |

© 2015 Advanced Instructional Systems, Inc. (revised November 2015)