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the sum of the coefficients of first three terms in the expansion of (x-3/x^2)^n, where n is a natural number, is 559 a):find the value of n b): find the term independent of x
The coefficients of the first three terms of are  m C0, (–3) m C1and (-3)2 m C2.

Therefore, by the given condition, we have
m C0 –3 m C1+ 9 m C2 = 559


since m is a natural number

? m = 12

Now, T r + 1 = 12C r x 12 – r = 12C r (– 3) r . x 12 – 3 r

Since we need the term containing x 3

? 12 - 3r = 3

? 3r = 12 - 3 = 9

? r = 3

Hence, the required term is 12C3 (– 3)3 x 3 =




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