Part a. We are given the following quadratic equation:
This is an equation of the form:
To complete the square we will add and subtract the following term:
Substituting we get:
Solving the operations and simplifying we get:
Therefore, the value of "c" is 9.
Part b. We will substitute the value of "c" in the equation:
Now, we solve the operation on the right side:
Now, we will factor the left side using the square of a binomial. Therefore, we take the square root of the first and third term and rearrange them in the form of the square of a binomial, like this:
This completes part B.
Part C. Now, we will solve for "x". To do that we will take the square root to both sides:
Now we add 3 to both sides:
Since we have a quadratic equation there are two possible solutions for "x". The first solution is determined using the plus sign:
The second solution is determined using the minus sign:
Therefore, the values of "x" are 5 and 1.