Answer:
Explanation:
Outline
You could have 2 values. The way to get them is to take the square root of 25, c is double the value you get for the first step. Why 25? Well you only have 1 other choice and that is the 1 that is in front of the x^2. That's not very helpful.
Formula
c = ± 2*sqrt(25)
Solution
c = ± 2 * sqrt(25)
c = ± 2 * 5
c = ± 10
Comment
Where does the ± come from?
You need to get + 25
If you have (x - 5)(x - 5) the last term will be -5 * - 5 = 25
Similarly you get the same result with (x + 5)(x + 5)