Question

Solve for x
5x^3-Ѵx=12

Answer 1

you on??

Answer 2

yeah

Answer 3

got to ask one question is there answer choices at all?

Answer 4

no u just give the answer to three decimal places

Answer 5

okay the final answer will X= 0.88834 and to go three place for final answer that was an sample only.

Answer 6

actually the answer 1.38

Answer 7

let me ask you what do you know about this problem, and what is it that is stumping you?

Answer 8

i dont know if i should use like logarithms or wat cuz its like part of functions

Answer 9

basically i dont know how to figure it out

Answer 10

this is not a function and here is the why, there is F(X) saying this.

Answer 11

no

Answer 12

okay in looking at the problem what can we do first?

Answer 13

because moving 5x^3 to other side where 12 is , would give us 12+5x^3

Answer 14

uh huh

Answer 15

actually it would be -5x^3

Answer 16

is it possible to use log?

Answer 17

no not in this problem

Answer 18

I am sorry for typo it is hard to see - these sometimes

Answer 19

yeah its fine ..

Answer 20

but you understood what I was doing right?

Answer 21

yeah i did go ahead

Answer 22

okay so now we -sqrt x= 12+5x^3 you agree with this?

Answer 23

yes

Answer 24

now we can get ride of the sqrt by squaring it.

Answer 25

how about if we take 12 to the other side and make it a cubic function does that make any sense

Answer 26

actually never mind that just doesnt make sense at all

Answer 27

no because 12 + 5x^3 we can take 5 three times and add 12 to it.

Answer 28

ure right

Answer 29

can you finish this?

Answer 30

nope not yet sorry

Answer 31

okay don't worry about the sqauare root yet, what is 5 times 5 times 5 equal?

Answer 32

125?

Answer 33

right now add 12 to and you get?

Answer 34

137

Answer 35

so now we have -sqrt x= 137 you agree?

Answer 36

yes

Answer 37

y are u adding instead subtracting?

Answer 38

cuz i was thinkng its 12-5^3?

Answer 39

opps right sorry

Answer 40

ok so with tat we have 113

Answer 41

and then u get root 113?

Answer 42

yes again sorry about the mistake, it is sometimes hard for me to do math with out writing the problem out somewhere bare with me.

Answer 43

dont worry ive done worse lol

Answer 44

okay so now we have -sqrt x= 113 so now the question becomes how to get the to be + and to get the x out of the sqrt. Any ideas?

Answer 45

well if i switch 113 to the other side its going be hard to get the root right?

Answer 46

because the answer has to + plus it must have some 1.4 so something what I am missing here?

Answer 47

due to that answer it means you must divide by something

Answer 48

alright ....

Answer 49

so b4 we move on the x^3 doesn't matter

Answer 50

really sorry if i'm not getting it right i

Answer 51

no not you the problem

Answer 52

one sec I have an idea will be back

Answer 53

yeah sure take ure time

Answer 54

don't leave

Answer 55

i wont

Answer 56

I have a friend coming to help as well just to another person here

Answer 57

sure

Answer 58

And now on with the problem lol

Answer 59

ikr

Answer 60

so were u right so far?

Answer 61

the question is now how to get ride of the -sqrt and have X= some 1 or 2.something?

Answer 62

actually two x's so i have no idea how to like solve it

Answer 63

wait how did get rid of the x^3? first

Answer 64

\[5x^3-\sqrt{x}=12\]\[-\sqrt{x}=12-5x^3\]\[x=(12-5x^3)^2\]\[x=(12-5x^3)(12-5x^3)\]\[x=144-120x^3+25x^6\]

Answer 65

what are we trying to do here?

Answer 66

we're having like an equation that looks cubic to me

Answer 67

solve for x and have be some 1.4 or something like that

Answer 68

\[0=25x^6-120x^3-x+144\]

Answer 69

yeah thanx got it

Answer 70

well guess I messed that one up, man I feel like wow!!

Answer 71

i here ya

Answer 72

I know where I went wrong, it is when we got rid of the 5x^3 that was the mistake. I was trying to make easy man

Answer 73

i was wishing it were that easy too XD

Answer 74

what gets me sometimes I mess up on the easy and get the hardest ones right I am not sure what to think at times.

Answer 75

ure lucky u get the hard ones buh yeah so far im gonna stare at the problem and sort try and fathom it and then i can try and work it out

Answer 76

buh thanx guys u really helped :)

Answer 77

hey no sweet may be next we do better what you say?

Answer 78

4 sure

Answer 79

just asking before I go, do you have any other problems that need help?

Answer 80

oh yes totally can i post right now?

Answer 81

yes sure

Answer 82

k

Answer 83

one at time plz lol

Answer 84

i can not see how to solve this problem

Answer 85

wow so we're in the same boat welcome right in

Answer 86

it's really an igcse qst and i'm learning the topic

Answer 87

i tried to use logs but it didn't help

Answer 88

So I was not alone in this nice lol