Answer: 25
Reason:
The exponent 25 is not a multiple of 3. If it was something like 24, then we would have a perfect cube as shown below
[tex]w = 125x^{18}y^3z^{24}\\\\w = 5^{1*3}x^{6*3}y^{1*3}z^{8*3}\\\\w=(5^1x^6y^1z^8)^3\\\\w = (5x^{6}yz^{8})^3\\\\[/tex]
When going from step 2 to step 3, I used the rule that [tex](abcd)^e = a^eb^ec^ed^e[/tex]. Basically the exponent e gets applied to each factor inside.
