Question

hi guys i have a question :(

Answer 1

Hi @rhcoballes I have a question too.. :(

Answer 2

\[\huge \color{green}{\textsf{Welcome To Openstudy..}}\]

Answer 3

can you help me? :)

Answer 4

I can tell this by looking at your question.. :)

Answer 5

do you know how to convert standard form to vertex form?

Answer 6

use completing the square method

Answer 7

Oh.. I can try..

Just post your question or an example you want to work on..

Answer 8

@HatcrewS let her start first.. :)

Answer 9

:)

Answer 10

x2-8x+5 :))

Answer 11

i dont have any idea how to convert standard form to vertex form

Answer 12

Any idea about Completion Of Square Method??

Answer 13

hmmm :3

Answer 14

yea :)

Answer 15

That is good..

Answer 16

im not good in math :(

Answer 17

Even I am not good.. :)

Answer 18

i need to explain and answer that question tomorrow so that i can have a plus 5 in our exam :)

Answer 19

So, let us solve our question now..

Can you try to use Completion of square method there?

Answer 20

You will have -5 if I explained you this concept.. :P

Answer 21

ughh help meee :(

Answer 22

\(y = x^2 -8x + 5\)

Use here Completion of square method..

Answer 23

x^2-8x+5 = x^2 - 2(4)(x) + 4^2 + 5 - 4^2
= [x^2 - 2(4)(x) +16] +5 - 15
= (x-4)^2 - 11

Answer 24

woooaahhh!

Answer 25

Thanks for doing it on my behalf.. :P

Answer 26

@UnkleRhaukus Hello..

Answer 27

You will be teaching me Differential Equation this entire year.. :)

Answer 28

i hope so

Answer 29

@HatcrewS can you explain it?

Answer 30

I also hope the same..

Answer 31

guysss helppp me :(

Answer 32

@rhcoballes but you told that you know about Completion of square method??

Or you mean to say that: you have seen a phrase called "Completing the Square Method" ?? :P

Answer 33

Vertex form of a quadratic equation is\[f(x) = a(x-h)^2+k\]where \((h,k)\) is the vertex

Answer 34

i forgot how to use that method :(

Answer 35

@HatcrewS how did you get the -15?

Answer 36

She has mistaken there..

It is \(-16\) there..

Answer 37

But final answer is correct.. \(+5 - 16 = -11\)

Answer 38

i have another example :)

Answer 39

Try to solve that.. :) You will get only if you do with your own hand.. :P

Answer 40

sorry it was -16 ><
i can teach u step by step if you wan to :)

Answer 41

@waterineyes i dont have idea how to do that.

Answer 42

do you have another example ? we can work frm there too if you want :D

Answer 43

3x2-10+2

Answer 44

what is the final answr of the 1st example?

Answer 45

that's our new lesson in math thats why i dont have idea.My teacher didnt teach us how to convert we dnt hve enought time

Answer 46

*enough

Answer 47

For Completing The Square (CTS) method: you need to be familar with (x+a)^2 and (x-a)^2
(x+a)^2 (vertex form) = x^2 + 2xa + a^2 (standard form)
(x-a)^2 (vertex form) = x^2 -2xa + a^2 (standard form)

We always use CTS method to convert from standard form to vertex form

So how do we actually do it ?
Consider x^2-8x+5,
We know that x^2-8x+5 does not convert to vertex form directly.
Lets leave +5 for a moment and focus on x^2-8x,

1. Since it is -8x, we know that x^2-8x will form (x-a)^2,
if it is +8x, it would be (x+a)^2.
2. we know that -8x = -2xa, hence -8x = -(2)x(a), and we have a=4 , because 4*-2=-8
3. Now, we have x^2-8x = x^2 - (2)x(4)
4. Since we know that a=4, by adding a^2, which is 4^2, to x^2-(2)x(4),
we have x^2-(2)x(4)+a^2 = x^2- (2)x(4) + 4^2
5(important). The thing is, we cant just add a value of 4^2 out of nowhere,
since we add 4^2 to x^2-(2)x(4), which becomes x^2-(2)x(4)+4^2, which also becomes (x-4)^2
we subtract 4^2 too, so that it is logical/justified.
6. Note that the original form is x^2-8x+5,
adding 4^2 ==> x^2-8x [+4^2] +5
subtracting 4^2 ==> x^2-8x [+4^2] +5 [-4^2]

and then we have (x-4)^2 + 5 [-4^2]
and it becomes (x-4)^2 +5-16
and we have (x-4)^2 -11
tadaa :D

Answer 48

hooooo!

Answer 49

how about my next example?

Answer 50

u try solving first

Answer 51

thanks