Question

find the value of n ​

Answer 1

Answer:

6

Step-by-step explanation:

Correct option is C)

Solution:

4

th

term i.e. T

4

in the expansion of (px+

x

1

)

n

=

n

C

3

×(px)

3

×(

x

1

)

n−3

Now,

T

4

=

n

C

3

×(px)

3

×(

x

1

)

n−3

or, T

4

=

n

C

3

×p

3

×x

6−n

Since, T

4

is indepemdent of x.

So, power of x i.e. 6−n should be zero.

or, 6−n=0

or, n=6

Hence, C is the correct option

Answer 2

Answer:

Step-by-step explanation:

[3/8]^-5X[3/8]^9=[3/8]^-2n-6

[3/8]^-5+9=[3/8]^-2n-6         [a^m+a^n=a^m+n]

[3/8]^4=[3/8]^-2n-6

4=-2n-6

10=-2n

-2n=10

-n=10/2

n=5(-1)

n=-5