Quadratic equations take the following form:ax² + bx + c = 0
Where x is the only variable and a, b and c are just numbers(Can be zero!).
If a=0: bx + c = 0
If b=0: ax² + c = 0
If c=0: ax² + bx = 0
Normally you have to find out the value of x.
E.g. x² - 121 = 0