Write the function in vertex form, and identify its vertex.
f(x) = x2 + 6x - 3
last question!

Question

Write the function in vertex form, and identify its vertex. 
f(x) = x2 + 6x - 3 
last question!

amistre64 · Answer

last question on the test?

anonymous · Answer

no my last question for the day

amistre64 · Answer

hmm, its hard to tell if that response is sarcastic or not lol

anonymous · Answer

its not.

amistre64 · Answer

:) +9-9 to complete the sqaure then tidy it up

ash2326 · Answer

We have
$$f(x)=x^2+6x-3$$
Let's add and subtract 9 to create square
$$f(x)=x^2+6x+9-9-3$$
$$f(x)=(x+3)^2-12$$
 Parabola's standard equation
$$f(x)=a(x+h)^2+k$$
the vertex is given as (-h,k)
here h=3 and k=-12
so vertex is (-3, -12)

amistre64 · Answer

or rather, lets add and subtract the square of half the x coeff

anonymous · Answer

thank you, ash. I see it now.

ash2326 · Answer

Welcome amy

amistre64 · Answer

(x+y)^2 = x^2 + 2y x + y^2

the middle term is just twice the compacted version of the square