y = -0.57x^2 + 6.79x - 16.68 how to put in general form showing all steps?

Question

dumbcow · Answer

its in standard form...do you mean vertex form?

anonymous · Answer

i need to know how to put it in general form

anonymous · Answer

from standart to general

dumbcow · Answer

$$y = a(x-h)^{2} +k$$
this form?

anonymous · Answer

yes

anonymous · Answer

i think its something with completing the square?

dumbcow · Answer

ok you have to use completing the square
haha

anonymous · Answer

lol well i figured:p i just for got how to do that :/

dumbcow · Answer

step 1: move constant to other side, and factor out coefficient of x^2 term

$$\rightarrow y+16.68 = -0.57(x^{2}-11.91x)$$
step 2: take half of x term and square it, then multiply by -.57 and add it to other side
$$\rightarrow y+16.68 -20.22 = -0.57(x^{2}-11.91x+35.475)$$
step 3: factor perfect square, simplify and move constants back to right side
$$\rightarrow y = -0.57(x-5.956)^{2}+3.54$$

anonymous · Answer

where did the 11.91x come from?

dumbcow · Answer

6.79/-.57 = -11.91..

anonymous · Answer

oh.. yeah i see my bad lol

dumbcow · Answer

it would be better to practice with easier numbers to get the hang of it first http://worksheetplace.com/mf/Completing-the-Square-1.pdf

anonymous · Answer

lol yeah im trying to figure out what you did but ill try the link thanks:)

dumbcow · Answer

sorry if i skipped steps...but i literally did exactly what i stated in each step

anonymous · Answer

http://www.khanacademy.org/math/algebra/quadtratics/v/completing-the-square BEST EXPLANATION EVER