Question

In the expansion of a binomial (a+b)^n the third term is equal to 56/9, the fourth term is 70/3, and the binomial coefficients of the third and the sixth term are equal. Find the values of a, b, and n​

Answer 1

$\huge\sf{\underline{\underline{\:\:\:\:spyXsenorita \: }}}$

m=1/2

Given (1+x)m

third term is 8−1x2

For (1+x)n the expansion is:

(1+x)n=1+nx+2!n(n−1)x2+....

So, the third term in (1+x)m is 2!m(m−1)x2

Solving:

=2m(m−1)x2=8−1x2

=2m(m−1)=8−1

=(m−1)=4−1

=m2−m+41=0

=4m2−4m+1=0

=(2m−1)2=0

∴ m=2