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#301 Re: Help Me ! » hi, any help with these two question? » 2016-12-23 10:09:07

Hannibal lecter

that is ok I'm keeping on, thank you

#302 Re: Help Me ! » hi, any help with these two question? » 2016-12-23 09:47:36

Hannibal lecter

I'll show you what I did,,,

when (x-9) (x-1) ≥ 0
(x-9) = 0 , x=9 the interval is [9,∞) , test a value between this interval : "10" : 10^2 - 10*10 +9 ≥ 0  , +9 ≥ 0  and that is true!
(x-1) ≥ 0 x=1 the interval is [1,∞) , test a value between this interval : "2" : 2^2 - 10*2 +9 ≥ 0 , -7 ≥ 0 , and that is WRONG! so Switch this inequality and become : x ≤ 1 ,  the  interval is : (-∞,1]

sol : (-∞,1] U [9,∞), except -3

is that ok? hehehe

#303 Re: Help Me ! » about Absolute Value.... » 2016-12-23 09:30:19

Hannibal lecter

I think I got is thanks for your help

#304 Re: Help Me ! » hi, any help with these two question? » 2016-12-23 09:28:09

Hannibal lecter

I mean how do you solve this ? what is the steps do it here please

#305 Re: Help Me ! » hi, any help with these two question? » 2016-12-23 09:18:10

Hannibal lecter

sure,,,  but what is the right answer now?

#306 Re: Help Me ! » hi, any help with these two question? » 2016-12-23 08:43:01

Hannibal lecter

but how that can be? x<= 1??

if we put -3 in it will be |-3+3| , zero,, and that is wrong right?

how did you do that

#307 Re: Help Me ! » hi, any help with these two question? » 2016-12-23 08:00:28

Hannibal lecter

I finish the first link math isfun.com

is the sol :  : [9,∞] ∩ [1,∞)

not U?

and if yes why ∩????

is cause will be either the first interval or the second one??

please I need answers I get board from trying I have a lot of topics in maths to finish sad

#308 Re: Help Me ! » hi, any help with these two question? » 2016-12-23 07:49:57

Hannibal lecter

I was study factoring and Quadratic Equations but I just started to study (Solving Quadratic Inequalities),

and I stuck with the first example,, I'll finish it...

#309 Re: Help Me ! » hi, any help with these two question? » 2016-12-23 06:37:23

Hannibal lecter

I think yes,  maybe

x-9 ≥ 0 =>>>>>>>>>  x≥9 then [9,∞)
and x-1≥0 =>>>>       x≥1    then [1,∞)

sol : [9,∞] U [1,∞)

is that right??  but the answer of my teacher is different???,



by the way thank you for this link I study the factors and quadratic equations,

#310 Re: Help Me ! » hi, any help with these two question? » 2016-12-22 14:34:53

Hannibal lecter

yes and what is the next

I mean I stuck in this point,,, what I have to do now?  please I want full solution I really have an exam after one week in such topics..

#311 Re: Help Me ! » hi, any help with these two question? » 2016-12-22 12:31:28

Hannibal lecter

these I'm while I'm trying to solve it myself :

like I said I stuck because of x^s and I stuck because of number 2 in the second question...

1482452951651.jpg

#312 Help Me ! » hi, any help with these two question? » 2016-12-22 12:03:45

Hannibal lecter
Replies: 27

hello
I tried to solve these two question about absolute value inequality but I stuck with x^2 and with number 2

please see this picture and solve this two for me,  the answer of my teacher for 1) is (-∞,1] U [9,∞)

and for 2) is (-∞,∞)

is it right?


I tried the a way that a member learned me that here but I stuck

solve this in short way for me please!!! it takes me 3 days and I didn't find any solution :

1482451359491.jpg[URL="http://www.up-0

#313 Re: Help Me ! » about Absolute Value.... » 2016-12-20 09:11:04

Hannibal lecter
zetafunc wrote:

can't be a solution, because
while

and what is that mean if I mean from where did you get |-1+3| there is just |x-3| and |x+1| in the expression I don't see |x+3|?
and do you mean it can't be equal to -1 because when we replace -1 by |x-3| ≤ |x+1| it will be |-1-3| ≤ |-1+1| then |-4| ≤ |0| and that is false it can't be -1, ... is that right? is I'm doing a good step or not....

zetafunc wrote:

So now you know that the values for which your inequality hold are:

and

The intersection of these sets is
. That is, the result of combining the above two inequalities is

To summarise, the left-hand side of what your lecturer wrote is fine. For the rest, see the above.


you said inequality are hold x > -1
and x ≥ 1.

so where is number zero?  why the inequality sol is not [0,∞) ?

#314 Re: Help Me ! » about Absolute Value.... » 2016-12-20 07:28:29

Hannibal lecter
Mathegocart wrote:

Sometimes it is more intuitive to explain it in the alternate form, which is also applicable for absolute values.
And yes, heed zetafunc's warning, sometimes it can introduce extraneous solutions.

may you please solve it like my lecturer did but in simple way without these strange number lines and +++ or ---

if you have a free time please, I need you sol with your elegant words and short steps. with greater and smaller and with interval notations.

#315 Re: Help Me ! » about Absolute Value.... » 2016-12-20 07:13:59

Hannibal lecter
zetafunc wrote:

The important part to take away from your lecturer's solution is that
is equivalent to

but mathegocart didn't do like the lecturer did, what does it changed? how the solution is

,

and the sol of the teacher is :

,
U {-1}.



zetafunc wrote:

it's important in general to go back and check whether or not the solutions you've found are actually valid.

but how to do that? I mean how to check wether or not the solution is valid or not????
how did you know the solution was fine please help with that...

#316 Re: Help Me ! » about Absolute Value.... » 2016-12-20 05:55:33

Hannibal lecter

Believe me if there is another way to help myself with, I'm sure I'll follow this way, but this is the only place that I can get help with a specific questions in math.
thank you very much.

so....is this the end of the solution? but how did you do that with an absolute value? ((( I mean we must take two possibilities once in >=0 and once in < 0 )))))???

please see this following picture, is the the solution of our lecturer in the university :- what is this? I really hop you to help me with full details about that


1482256157981.jpg




I always asking him about problems but our lecturer don't show respect to who ask him about that he learning us he just writing these problems without careful and caring sad ...

#317 Re: Help Me ! » about Absolute Value.... » 2016-12-19 08:36:50

Hannibal lecter

thank you for this great example,

can I ask you another question it was difficult to me to solve it :-

<=

or like this

<= 1

please may I get the full solution for this? with its interval notation

#318 Re: Help Me ! » LaTeX - A Crash Course » 2016-12-19 07:42:12

Hannibal lecter

thanks,,, and maybe I need to put a root inside this fraction

what can I write

#319 Re: Help Me ! » LaTeX - A Crash Course » 2016-12-19 00:42:25

Hannibal lecter

how to write the number line? and how to write the numerator and denominator fractional and how to put a variables inside the absolute value? I mean inside bars | | | | ?

#320 Re: Help Me ! » about Absolute Value.... » 2016-12-17 12:15:42

Hannibal lecter

thank you very much Mathegocart

can I ask another question?

what is that mean :

1482020053631.png


what i u ?
and why +-a

#321 Re: Help Me ! » about Absolute Value.... » 2016-12-16 22:53:46

Hannibal lecter

thank you bobbym,


and #zetafunc sorry but I don't understand these symbols you provided, I'm not like you I just do simple mathematics I don't even know what is


and I wish to know what is these beautifull symbols
sorry

#322 Re: Help Me ! » about Absolute Value.... » 2016-12-16 22:50:06

Hannibal lecter

#Mathegocart

yes thank you very much I got it now.

but can we say the abs -6 is -6 too? cause it is just a sign. what will happen if we say that

#323 Introductions » Hi, » 2016-12-16 22:36:02

Hannibal lecter
Replies: 2

Hello, .... I'm zaid and nice to meet you all


I just feel that I'm very annoying here and don't make people feel happy

because I ask too much then usual ( that because of my bad past in mathematics). so if anyone feel that I'm disturbed just tell me and I'll leave the forums.
or if anyone from this point that have an advice for me, please go ahead and tell me.


Greeting

#324 Help Me ! » about Absolute Value.... » 2016-12-16 15:51:10

Hannibal lecter
Replies: 23

Hi,

I study the absolute value maybe more than 2 times in my life,, when I was in the school and now and on the internet for myself

now I read (Absolute Value  how far a number is from zero) .. then it is mean abs for 6 is 6 and -6 is 6

what is the meaning of that? and if it was about how far the number 6 from zero is the meaning of abs
then why -6 is 6 ? why the abs -6 is -6?



I apologize for such questions again and again.. I don't have another way to understand! sorry

#325 Re: Help Me ! » question about an example I saw at math is fun » 2016-12-16 15:45:39

Hannibal lecter

thank you very much ...

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