What is the natural number n for which (3^9 + 3^{12} + 3^{15} + 3^n) is a perfect cube of an integer?

examrobotsa's picture
Q: 40 (CAPF/2019)
What is the natural number n for which (3^9 + 3^{12} + 3^{15} + 3^n) is a perfect cube of an integer?

question_subject: 

Maths

question_exam: 

CAPF

stats: 

0,2,10,5,4,1,2