Question

What are the real or imaginary solutions of the polynomial equation?

27x^3 + 125 = 0

Answer 1

@Luigi0210 i know ur probably tired of explaining these things to me but could u help me again? like do i just factor this as well?

Answer 2

Starts by getting x by itself.

Answer 3

27x^3 + 125 = 0
Divide both sides by 27
x^3 + 4.6296296296 =0

Answer 4

so far i have 27x^3+125=0
then i subtracted 125 from each side which gives me 27x^3= -125
after that i divided each side by 27 so now i have x^3= -4.63
so now what do i do?

Answer 5

Take the cube root of -4.63

Answer 6

Ah, there's both of your guy's mistakes. When you divide, don't simplify it into a decimal, just leave it as a fraction.

Answer 7

So you'll have:
\[\LARGE -\frac{125}{27}\]
Now take the cubic root of each:
\[\LARGE -\frac{5}{3}\]

Answer 8

so x would equal -5/3?

Answer 9

Yup, when you take a cubic root, anything that isn't even, you are allowed to take the negative root of it.

Answer 10

Well I used a calculator to determine the cube root of -4.6296296296 and it's
-1.6666666667

and -5/3 = -1.6666666666666666

Answer 11

Yea, both methods work, but leaving it in fractions will give you a precise answer, while decimals are just an approximation.

Answer 12

ok so when it says What are the real or imaginary solutions of the polynomial equation?
all i have to do is say that the answer is i 5/3 ? or 5/3i or i(5/3)

Answer 13

no the answer is actually -5/3

Answer 14

Yea, you only get imaginary answers when it is squared and it has a negative.

Answer 15

So it's -5/3

Answer 16

You can take a cube root of a negative number.

Answer 17

ohh ok its slowly making sense now :) thanks guys ^_^

Answer 18

u r welcome :-)

Answer 19

Anytime Alleyyyy

Answer 20

oh quick question do you know how to take the cubic root on a TI-84 calc?

Answer 21

I don't know if it has the cube root function.
But look for a key that looks like this

Answer 22

The Ti-84 does actually have that function, I just need to find mine.

Answer 23

Okay that's just square root - NOT what you need.
Look for a key that looks like this

Answer 24

wolf this is what my calc looks like the gray one. on the right

Answer 25

Screw it, I can't find it. Just use the exponential function. Make sure to use the parenthesizes

Answer 26

ok maybe i will google it :\ i have 2 more question mind helping?

Answer 27

Heck - okay

Answer 28

i tagged you in it :)