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, in each side of the equation, one to one. In 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, and the right side, and the inequality symbol. Then each element of the student answer must be mathematically equivalent to each of the correct answer.

Consider the following question:

with correct answer:

Student answer Validation
left parenthesis x minus 1 right parenthesis squared plus left parenthesis y minus 2 right parenthesis squared equals 9
x squared minus 2 x plus 1 plus y squared minus 4 y plus 4 equals 9
x squared plus y squared minus 2 x minus 4 y plus 5 equals 9
x squared plus y squared minus 2 x minus 4 y equals 4
x squared plus y squared minus 2 x minus 4 y minus 4 equals 0