Answer:c = ±
Step-by-step explanation:Before we begin, remember the following:(x)² = (-x)² = x²
√x² = ±x
Now, for the given:To solve for c means that we need to isolate the c on side of the equation.
This can be done as follows:
c² - 9 = b²
Add 9 to both sides of the equation:
c² - 9 + 9 = b² + 9
c² = b² + 9
Now, take the square root for both sides of the equation. Don't forget the the square root gives a positive and a negative value.
√c² = √(b²+9)
c = ±

Hope this helps :)