Which number in the monomial 215x^18y^3z^21 needs to be changed to make it a perfect cube ?

Hello from MrBillDoesMath!

 215

Discussion:

Let's start by rewriting the monomial as

215  x^18 y ^3 z^21

Now..

x^ 18 = (x^6)^3

y^3   = (y    )^3

z^21 =  (z^7)^3

So those terms are already cubes!  The only remaining candidate is the number 215, which is not a cube.

Thank you,

MrB

step-by-step explanation:

0

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.