Answer:
<em>C) 7</em>
Step-by-step explanation:
<u>Quadratic equation</u>
The quadratic equation can be written in several ways, one of the most-used is
To rewrite the equation in the form
we can complete squares and rearrange the terms as follows. The provided equation is
The second term can be seen as
And the first two terms can be visualized as the square of a binomial
We have added and subtracted 81 to complete the square and not modify the equation. The new form of the equation is
Rearranging
Comparing with the general form written above, we find that