Binomial Theorem · JEE Advanced previous year questions

2023 1 question

1. Q132023 · 4 Jun 2023 · Paper 1· Numerical answer

   Let $a$ and $b$ be two nonzero real numbers. If the coefficient of $x^5$ in the expansion of ${\left(a{x}^2+\frac{70}{27bx}\right)}^4$ is equal to the coefficient of $x^{-5}$ in the expansion of ${\left(ax-\frac{1}{b{x}^2}\right)}^7$, then the value of $2b$ is ____.

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   Answer: 3