Question

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

Answer 1

Answer:

c=36

Step-by-step 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.