Question

Determine the solution set for z:
z6 - 4z5 - 30z4 = 0
-3, 5
0,-3, 5
3, -5
0, 3, -5

Answer 1

Hi there!

Answer 2

Hi can you help me?

Answer 3

Yep! Ready?

Answer 4

Yes

Answer 5

Okay! See, there are several methods of finding the solution set.

Let's start with the trickiest one:

Put the value of z from each option into the equation and see if the solution is valid. If yes, then you have your solution set, else continue to next option

Answer 6

Need an example ?

Answer 7

Is the answer 0, -3, and 5

Answer 8

Give me a moment. I will check it ou

Answer 9

Okay

Answer 10

z = 0 is correct. But, check again for the rest ones

Answer 11

So it's the last choice?

Answer 12

Am I right?

Answer 13

Are you sure the question is correct ? I mean can you please recheck the equation once ?

Answer 14

Determine the solution set for z:
z6 - 4z5 - 30z4 = 0

-3, 5
0,-3, 5
3, -5
0, 3, -5

Answer 15

That's the question given to us

Answer 16

I think there is some mistake in question:

See, the reason is this:

\[\large{z^6 - 4z^5 - 30z^4 = 0}\]
\[\large{z^4(z^2 - 4z - 30) = 0}\]

Now, there are two possibilities for this:

1. \(\large{z^4 = 0} \implies z = 0\)

2. \(z^2 - 4z - 30 = 0 \implies z = 2 - \sqrt{34} \text{ or } z = 2 + \sqrt{34}\)

Answer 17

So, there is some mistake in the question or in the options

Answer 18

I'm getting graded on this questions what do I choose?

Answer 19

I tell you what: Write "none of the options is correct" and go to your teacher and request for clarification.

And, if possible, include the solution I wrote above. It will help you :)

Answer 20

There's no option for it only pick a choice

Answer 21

Can anyone else solve it and do they get the same as you?

Answer 22

Well, wolframalpha solved it and got the same thing...

I would say go for (b) or (d) --> whichever one you want as both are wrong in reality :D

Answer 23

http://www.wolframalpha.com/input/?i=z%5E6+-+4*z%5E5+-+30*z%5E4+%3D+0

Answer 24

I don't know what to do?!

Answer 25

plug solution into the equation if both sides are equal then those two number would be your answer
let's see if its work...

Answer 26

Idk how to!

Answer 27

Is it any to the choices?

Answer 28

I mean any of the choices?

Answer 29

like vishweshshrimali5 says .
seems like there is an error
for sure 0 is one of solution

Answer 30

the zeros he/she got are 2 -sqrt{34}
and 2+sqrt{34} use calculator and change it to decimal you will get another hint :-)

Answer 31

I got 7.83095189485

Answer 32

what about the first one ?

Answer 33

-3.83095189485

Answer 34

What do I do with those numbers?

Answer 35

2nd one is negative 3.83
seems like it can be one of solution
hmmm it can be 4
strange....

Answer 36

i'll go with -3.83

Answer 37

good luck!
check ur question one more time :-)

Answer 38

Okay thanks