# Mathematically equal

The Mathematically equal option will work fine in most cases, and it can handle equations, but it has some restrictions. In this mode, the student and the correct answers must have equivalent expressions on each side of the equation one to one. In the case of inequations, the inequality symbols must also be the same.

You better think of an equation as a list with three elements: the left side, right, and inequality symbol. Then each element of the student answer must be mathematically equivalent to each correct answer.

## Example: Equation of a circumference

Consider the following question:

with correct answer:

Then, the following answers will be accepted or rejected according to the table below:

Student answer | Validation |
---|---|

$(x-1{)}^{2}+(y-2{)}^{2}=9$ | |

${x}^{2}-2x+1+{y}^{2}-4y+4=9$ | |

${x}^{2}+{y}^{2}-2x-4y+5=9$ | |

${x}^{2}+{y}^{2}-2x-4y=4$ | |

${x}^{2}+{y}^{2}-2x-4y-4=0$ |