Question

if the coefficient of x7 and x8 in the expansion of the 2+x/3 are equal then n is​

Answer 1

Answer:

55

Step-by-step explanation:

okay,

for x7

T7+1= nc7*(2)n-7 *(x/3)7, T8+1=nc8*(2)n-8*(x/3)8

  n!   * (2)n-7*(x7)/(3)7=      N!*  (2)n-8 *x8/(3)8

7!(n-7)!                                8!(n-8)!

n! cancel n! and (n-7)*(n-8)!=(n-8)! here n-8! cancel out each other

3 7 and 3 8 here 3 8 cancel 3 7 and remaining 3 and (2)n-7/(2)n-8   = (2)1  

now we have

8/n-7 =1/6

n=55