How to solve a geometry problem

The variable in a relation who’s value depends on the value of the independent variable is called what?

The lengths of two sides of a right triangle are given. find the length of the third side. round to the nearest tenth if necessary. a) y = 12/5x + 39/5 b) y = 5/12x + 5/39 c) y = 12/5x - 39/5 d) y = 5/12x - 5/39

Aquadratic equation in standard from is written ax^2= bx+c, where a,b and c are real numbers and a is not zero?