Explanation:
(3x-2/x)^10
(r+1)th term = 10Cr (3x)^10-r (-2/x)^r
= 10Cr (3)^10-r (-2)^r (x)^10-2r
Let 10-2r = 12
- 2r = 2
r= - 1
The coefficient of x^12
= 10C-1 (3)^11 (-2)^-1
= 10C11 (3)^12 (-1/2)
= (1/11) (3)^12 (-1/2)
= - 1/22 × (3)^12
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