Let \( \Large f \left(x\right)=3x^{5}+9x^{4}-7x^{3}-5x^{2}-3ax+3a^{2} \)
This function is divisible by \( \Large x-1,\ if\ f \left(1\right)=0 \)
\( \Large \therefore f \left(1\right) = 3+9-7-5-3a+3a^{2} = 0 \)
=> \( \Large 3a^{2}-3a = 0 \)
=> \( \Large a \left(a-1\right)=0 \) \( \Large \left[\because 3 ≠ 0 \right] \)
=> a = 0, 1