Question

find all zeros for each function. x^4-4x^3-16x^2+21z+18 Please help!!

Answer 1

@hartnn please help!!!

Answer 2

so stuck

Answer 3

u have options/choices ?

Answer 4

no i dont

Answer 5

ok, then lets use rational root theorem

Answer 6

which says that the possible roots can be factors of +-18/1

Answer 7

can u factor 18 ?

Answer 8

yeah so 1,18 6,2

Answer 9

and 3 ?

Answer 10

3,9

Answer 11

opps not 9

Answer 12

ok, its easy to find that 1 is not the root,lets try 6

Answer 13

k

Answer 14

put x=6 in that, does that expression become 0 ??

Answer 15

hold on

Answer 16

k, take your time...

Answer 17

into the originak equation

Answer 18

original

Answer 19

yes.
put x=6 in x^4-4x^3-16x^2+21z+18

Answer 20

480

Answer 21

i am getting 0....

Answer 22

really let me try again

Answer 23

that z is actually x , right ?

Answer 24

yeah!

Answer 25

so it 6

Answer 26

6 is one of the ZERO of that function.
there will be total 4 zeros.

Answer 27

ok....

Answer 28

so, divide that function by x-6
u get a cubic equation....

Answer 29

what does that look like..

Answer 30

know about synthetic division ? or long division ?

Answer 31

yeah sort of

Answer 32

i think i got what you are saying