Let a5b7 occurs in the (r + 1)th term, in the expansion of (a - 2b)12 given by I2Cr. a12 – r(-2b)r. Then 12 – r = 5. This gives r= 7.
Thus the coefficient of a5b7 is
12C5 (-2)7 = (-128) = (792) (-128) = -101376
Rate this question :
How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
view all courses
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation