Question

Determine whether the following equation defines y as a function of x: x^2 + y^2 = 169. How was this solved? Where does the 2 (pictured) come from?

Answer 1

Explanation:

Assuming you can follow how the equation was solved for y, the 2 comes from the "±" in front of the square root. That means that there is a positive and a negative result when you plug in a number for x. For example, if we were asked to solve

`x^2=4`

we would take the square root of both sides, giving us

x = ±2

This is because a positive 2 squared gives us a positive 4, and a negative 2 squared also gives us a positive 4. There will ALWAYS be 2 solutions when you take a square root of a number, both the positive (principle) and negative roots.