Question

What is the value of c so that -12 and 12 are both solutions of x^2-c=108? ​

Answer 1

c=36

Explanation:

1. Because
   `x^2-c=108` can be rewritten as
   `x^2-c-108=0`, finding the value of c so that x=(+-)12 solves this equation it means to find the value of c so that
   `(+-)12^2-c-108=0`.
2. Because
   `12^2=(-12)^2=144`, we must find c so that
   `144-c-108=0`.
3. Because
   `144-108=36`, c=36.
4. To check, replace c=36 in the initial equation, and check it is a solution for x=(+-)12.