defence exam Coast Guard Navik GD (General Duty) 02/2025 Mock Test Series Mathematics Binomial Theorem Special Terms of Binomial Expansion
If the coefficients of x2 and x3 in the expansion of (3 + ax)9 are the same, then the value of a is:
1
\(\frac79\)
2
\(-\frac79\)
3
\(\frac97\)
4
\(-\frac97\)