Question

Which of the following represent the zeros of f(x) = 6x^3 – 29x^2 – 6x + 5

5, 1/3, -1/2

5, -1/3, 1/2

-5, 1/3, -1/2,

5, 1/3, 1/2

Answer 1

@phi

Answer 2

I would test each choice in the original equation and see if I get 0

Answer 3

To test it what do I replace? If I was testing the first one would it look like this:

f(x) = 6(5)^3 – 29(1/3)^2 – 6(-1/2) + 5

Answer 4

you replace x with the same number. so you can test +5 by replacing all x's with 5

Answer 5

If you get 0 with x=5, that tells you choices A, B and D are possible answers.
then check the next number.

Answer 6

Well 6*5=30 and 30 cubed = 27000

and

29*5=145 and 145 squared = 21025 So it couldn't be those 3 could it?

Answer 7

I don't think it could be -5 either though

Answer 8

6x^3 means 6*x*x*x
if x is 5, it is 6*5*5*5
or 6* 5^3 if you use a calculator

Answer 9

750

Answer 10

so you have to be careful
6x^3 – 29x^2 – 6x + 5

6*5^3 - 29* 5^2 -6*5 + 5

Answer 11

ohh

Answer 12

750-725-30+5=0

Answer 13

yes, that makes sense. so you can cross of choice C
now test ⅓

Answer 14

I did \[6\times \frac{ 1 }{ 3 }^{3}\] and got 0.22222

Answer 15

yes. with ⅓ I would put ⅓ into a variable in the calculator (if you know how)

Answer 16

I don't...

Answer 17

ok, then keep going... -29*(⅓)^2

Answer 18

-3.22222...

Answer 19

if you add the first term 0.22222 you get -3
so far.
now – 6x

Answer 20

I put the fraction in parenthesis and got -3.625

Answer 21

I don't know how you got -3.625

so far you found
6 *(⅓)^3 = 0.22222
-29*(⅓)^2 = -3.22222
which add up to -3

now -6x+5

Answer 22

Wouldn't it add up to -3.44444

Answer 23

+0.2222 - 3.2222

maybe it is easier to see if you look at a similar problem
+0.5 - 1.5 (plus ½ take away 1 and ½ , leaves -½)

Answer 24

-6*1/3=-2
-3+-2=-5
5+-5=0

Answer 25

the first line is ok -6*⅓ is -2

now add +5
+5 -2 is +3

all together,
6 *(⅓)^3 = 0.22222
-29*(⅓)^2 = -3.22222
-6x = -2
+5 = +5
now add up all of those numbers.

Answer 26

6*-1/2^3=-0.75
29*-1/2^2=-7.25
6*-1/2=-3+5
-0.75-7.25-3+5=-6

Answer 27

I added those already above

Answer 28

I think you have to be careful of the signs.
notice in the equation it is
-6*x
if x is -½ , this is -6*-½ = +3 (not -3)

Answer 29

Ohhh

Answer 30

So it would be 0 :D

Answer 31

Thanks Phi!

Answer 32

I have another question though...

Answer 33

It's unrelated to this one

Answer 34

Which polynomial identity will prove that 37 = 64 − 27

Answer 35

yes, and your second line
29*-1/2^2=-7.25
is the correct number, but you should have said
-29* (-½)^2

the -½ * -½ = +¼ , and -29* ¼= -7.25

Answer 36

My answer choices are:
difference of squares
difference of cubes
sum of cubes
square of a binomial

I would guess it's sum of cubes because it's adding but there are no cubes...

Answer 37

4*4*4
and 3*3*3

Answer 38

What do you mean?

Answer 39

what do you get if you multiply out 4*4*4 or 3*3*3 ?

Answer 40

Maybe it's not sum of cubes, it's not adding. Idk what i was thinking

Answer 41

64 and 27 which are cubes

Answer 42

and its subtracting

Answer 43

is it difference of cubes?

Answer 44

that would be my guess.

Answer 45

So would 49 − 4 = 45 be difference of cubes?

Answer 46

49 and 4 are cubes and its subtracting

Answer 47

looks like it:
7^2 - 2^2 - 45

Answer 48

=45
that looks like a difference of squares.

Answer 49

You were right, thank you :)