# Find the 4th term from the end in the expansion of (x32-2x2)9 - Mathematics

Sum

Find the 4th term from the end in the expansion of (x^3/2 - 2/x^2)^9

#### Solution

Since rth term from the end in the expansion of (a + b)n is (n – r + 2)th term from the beginning.

Therefore 4th term from the end is 9 – 4 + 2

i.e., 7th term from the beginning

Which is given by T7 = ""^9"C"_6 (x^3/2) ((-2)/x^2)^6

= ""^9"C"_3 x^9/8 * 64/x^12

= (9 xx 8 xx 7)/(3 xx 2 xx 1) xx 64/x^3

= 672/x^3

Concept: Binomial Theorem for Positive Integral Indices
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#### APPEARS IN

NCERT Mathematics Exemplar Class 11
Chapter 8 Binomial Theorem
Solved Examples | Q 3 | Page 132
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