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If (1+a x)^n=1+8 x+24 x^2+\ldots .  then the value of a and n is

Option: 1

2, 4


Option: 2

2, 3


Option: 3

3, 6


Option: 4

1, 2


Answers (1)

best_answer

As given (1+a x)^n=1+8 x+24 x^2+\ldots

\begin{aligned} & \quad 1+\frac{n}{1} a x+\frac{n(n-1)}{1.2} a^2 x^2+\ldots=1+8 x+24 x^2+\ldots \\ & \Rightarrow n a=8, \frac{n(n-1)}{1.2} a^2=24 \Rightarrow n a(n-1) a=48 \\ & \Rightarrow 8(8-a)=48 \Rightarrow 8-a=6 \Rightarrow a=2 \Rightarrow n=4 \end{aligned}

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HARSH KANKARIA

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