Question

In the 10th term of $(x+y{)}^n$, the exponent of x is 3, then the exponent of x in the 7th term is ....... .

• A. 3
• B. 6
• C. 5
• D. 7

Answer 1

Answer: (B)

6

The given expansion is $(x+y{)}^n$.

$T_{10}=T_{9+1}={n_C}_9\left(x{)}^{n-9}\right(y{)}^9$

Given, $n-9=3$

$n=12$

$T_7=T_{6+1}={{12}_C}_6{x}^6{y}^6$

Therefore, exponent of x is 6.