Question

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

Answer 1

what is "general form"? looks like it is already in standard form

Answer 2

idk... some people are saying its standard form and others are saying its general so im way confussed..

Answer 3

wonder if this is the genral form f(x) = a(x - h)2 + k.......i think it's already in gen form....is it about conics?

Answer 4

then i thought i was in general form already to until i saw ppl saying it was standard.. i think this one is standard f(x) = a(x - h)2 + k
and this one is general form f(x) = ax2 + bx + c
so it would be as my equation and i would have to change it to standard?

Answer 5

may be...u kno how to solve it r8

Answer 6

if it's standard

Answer 7

no i dont ..

Answer 8

um ok......if u have a.x2 + bx + c......
a(x^2 + kx)+c
a(x^2+ kx+p - p)+c .....
a(x^2 +kx + p) +c-ap....
a(x - h)2 + k

Answer 9

here is the answer i got ... y = -0.57 (x - 6.79/ 0.57) ^2 + (46.1041/ 2.28) - 16.68 i just need to know if its right or not?

Answer 10

um....m lazy....

Answer 11

haha thats fine! thanks anyway :)

Answer 12

wait you want it in vertex form?
\[y=a(x-h)^2+k\]?

Answer 13

we can do that no problem, if that is what you want

Answer 14

oh wait, looks like you have already done it, but there is a mistake

Answer 15

well i can show you my work if that would help?

Answer 16

\[y = -0.57x^2 + 6.79x - 16.68\]
\[y=-.57(x^2-\frac{6.79}{.57}x)-16.68\]
\[y=-.57(x-\frac{6.79}{1.14})^2-\text{something}\]

Answer 17

you jumped a step. you have to factor out the -.57 first, then take half the coefficient of the middle term to complete the square

Answer 18

these decimals are as annoying as can be, but i guess you are supposed to approximate. it doesn't really make sense to have one decimal divide by another, so you can either use a calculator and divide or else you could write
\[y=-.57(x-\frac{679}{114})^2+\text{something}\] and you can find "something" by replacing \(x\) by \(\frac{679}{114}\) in the original expression to see what you get

Answer 19

my guess is you are supposed to use a calculator to get it

Answer 20

for the record the answer is
\[y=-.57(x-\frac{679}{114})^2+\frac{80737}{22800}\]

Answer 21

general idea is that if you start with
\[y=ax^2+bx+c\] you go to
\[y=a(x^2+\frac{b}{a}x)+c\] to
\[y=a(x+\frac{b}{2a})^2+\text{something}\] and the something is what you get when you replace \(x\) by \(-\frac{b}{2a}\)

Answer 22

yeah i know their annoying i had to do an activity to where i had to graph a parabola and this is the equation i had to work with sadly .. but thanks, you helped me alot!

Answer 23

if you want to graph it, take a look here
http://www.wolframalpha.com/input/?i=y+%3D+-0.57x^2+%2B+6.79x+-+16.68+
also if you want to see it in vertex form, look at the very bottom where it says what the max is and what value of x gives it to you
match it up to what i wrote above, and you will see it

Answer 24

oh okay well i did the graph