Question

Can i get some help on this one?

Answer 1

`(x+9)^2=-4`

Step by step explanation:

Completing the square is where we take a quadratic equation like this:

`\begin{gathered} ax^2+bx+c=0 \\ \text{ and turn it into this:} \\ a(x+d)^2+e=0 \end{gathered}`

Where d and e can be represented by the following expressions:

`\begin{gathered} d=(b)/(2a) \\ e=c-(b^2)/(4a) \end{gathered}`

Since we have the following equation:

`\begin{gathered} x^2+18x+74=-11 \\ x^2+18x+85=0 \end{gathered}`

So, for a=1, b=18 and c=85.

Find d and e:

`\begin{gathered} d=(18)/(2)=9 \\ e=85-(18^2)/(4)=4 \end{gathered}`

Then, the result for completing the square would be:

`\begin{gathered} (x+9)^2+4=0 \\ (x+9)^2=-4 \end{gathered}`