Question

Solve x3 = 64 over 27.
±8 over 3
8 over 3
±4 over 3
4 over 3

Answer 1

@phi

Answer 2

you could check your answer choices

Answer 3

this isnt the one that needs checking

Answer 4

x^3 means x*x*x
so you could check if the answer times itself 3 times gives 64/27

Answer 5

I am suggesting a way to decide what the answer is.
one way is to check each of the 4 possible answers. only one of them should "work"

Answer 6

the other way to answer the question is to "solve for x"
but that involves finding cube roots.

Answer 7

hmmm

Answer 8

let me look rlly fast

Answer 9

im not sure

Answer 10

let's test x= 8/3
what is \[ \frac{8}{3} \cdot \frac{8}{3} \cdot \frac{8}{3} \]
multiply top times top and bottom times bottom

Answer 11

512/27?

Answer 12

@phi is that it

Answer 13

yes and 512/27 is not 64/27
in other words, 8/3 (and also -8/3) is not the answer

the other two choices are 4/3 and \(\pm\) 4/3
the only difference is the second choice includes -4/3
but -4/3 * -4/3 * -4/3= -64/27
it is negative and we want +64/27

that means the only answer that works is 4/3