Answer:
Step-by-step explanation:
3240 is a perfect cube if 3240 = n³ (n ∈ N).
Use the Prime Factorization:
[tex]\begin{array}{c|c}3240&2\\1620&2\\810&2\\405&5\\81&3\\27&3\\9&3\\3&3\\1\end{array}\\\\3240=2\cdot2\cdot2\cdot5\cdot3\cdot3\cdot3\cdot3=2^3\cdot3^3\cdot5\cdot3=(2\cdot3)^3\cdot5\cdot3=6^3\cdot5\cdot3[/tex]
[tex]3240=6^3\cdot15\qquad\text{multiply both sides by}\ 15^2\\\\3240\cdot15^2=6^3\cdot15^3=3240\cdot15^2=(6\cdot15)^3=90^3[/tex]
Used:
[tex]a^n\cdot a^m=a^{n+m}\\\\(ab)^n=a^nb^m[/tex]