simply -2x cube root of 27 *3. My book says the answer is -6x cube root 3x. I can't figure out how to get the -6x?

Question

simply -2x cube root of 27 *3.  My book says the answer is -6x cube root 3x.  I can't figure out how to get the -6x?

tkhunny · Answer

$$-2\cdot \sqrt[3]{27} = -2\cdot 3$$  It's not real clear what shoudl be done with that 'x'.  It's just kind of floating about with no guidance.

anonymous · Answer

the full problem is -2x$$-2xsqrt[3]{81x}+4\sqrt[3]{3x ^{4}}$$

anonymous · Answer

I simplified the cube root of 81x to cube 27 * 3x.  the cube of 27 is 3 so i don't understand how the book comes up with $$x6\sqrt[3]{3x}$$

phi · Answer

-2 out front

anonymous · Answer

|dw:1351088326344:dw|

phi · Answer

$$ -2x\sqrt[3]{81x}+4\sqrt[3]{3x ^{4}} $$
$$ -2x \cdot 3 \sqrt[3]{3x} + 4 \cdot x\sqrt[3]{3x} $$

phi · Answer

that simplifies some more...

anonymous · Answer

ok, i understand, I was adding not multiplying.  I knew it was something stupid and little just don't know why I couldn't figure that one out.  Thanks so much.

phi · Answer

to finish this
$$ -6x \sqrt[3]{3x}+4x\sqrt[3]{3x}= -2x\sqrt[3]{3x}$$