Question

Using the completing-the-square method, rewrite f(x) = x2 + 10x + 7 in vertex form

Answer 1

@ganeshie8 @dan815 @Kainui @Michele_Laino @DanJS

Answer 2

hint:
we can add and subtract 25, so we can write this:
\[\Large \begin{gathered}
f\left( x \right) = {x^2} + 10x + 7 = \hfill \\
\\
= {x^2} + 10x + 25 - 25 + 7 \hfill \\
\end{gathered} \]

Answer 3

What does that do? confused

Answer 4

we have:
\[\Large {x^2} + 10x + 25 = {\left( {x + 5} \right)^2}\]
am I right?

Answer 5

f(x)=(x+5)^2-18
f(x)=(x+10)^2+25
f(x)=(x+5)^2+7
f(x)=(x+5)^2

Those are my options btw

Answer 6

so, what is the right option? Please look at my second hint

Answer 7

I'd say B

Answer 8

sorry, it is not B

Answer 9

hint:
\[\Large \begin{gathered}
f\left( x \right) = {x^2} + 10x + 7 = \hfill \\
\hfill \\
= {x^2} + 10x + 25 - 25 + 7 = \hfill \\
\hfill \\
= {x^2} + 10x + 25 - 18 \hfill \\
\end{gathered} \]

Answer 10

please keep in mind that:
\[\Large {x^2} + 10x + 25 = {\left( {x + 5} \right)^2}\]

Answer 11

So its A?

Answer 12

yes! that's right!

Answer 13

Thank you!!

Answer 14

:)