Plz tell me if the quadratic function is really x=-b plus or minus the square root of b squared minus 4ac all over 2a?

Ineed to know the answer to this algebra question.

Lucy and donavan measured the length of the school garden. lucys measurement is 11.3m and donavans measurement is 113 cm. could both be correct? explain

If two points are given,then exactly one line can be drawn through those two points.which geometry term does the statement represent