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Best answer

Use Binomial Theorem simply ,

So rth term in the given binomial expansion will be :

(-1)^{r }. ^{n}C_{r} (x^{2})^{n}^{-r }(1/x)^{r} ; here n = 100

==> (-1)^{r} . ^{n}C_{r }x^{200 - 3r} = x^{198}

But equating 200 - 3r and 198 we get r = 2 / 3 which is not an integral value..

**But we require that r be an integer as it is used in binomial coefficient ^{n}C_{r}..**

**Hence there is no term containing x ^{198}..**

**So coefficient of x ^{198} in the given binomial expansion = 0**