Question

The term independent of x in the product of :
(4 + x + 7x^2)[ x - 3/x]^11
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Answer 1

Answer:

General term of (x-3/x)^11 is

11Cr (x)^11-r (-3/x)^r = 11Cr(-3)^r (x)11-2r

Clearly, for integer values of r, there will only be odd so, let's see the term where power of becomes -1 so that when multiplied with the First bracket, the power of x becomes zero with multiplication with x in the first bracket.

So, 11-2r=-1 => r = 6

So,

The term independent of x is

11C6(-3)^6 = 11C6*(3)^6

Hope this helps you !