If sum of the coefficients of the first, second and third terms of the expansion of x2+1xm is 46, then the coefficient of the term that does not contain x is

Given, mC0+mC1+mC2=46⇒        2m+m(m−1)=90⇒        m2+m−90=0⇒m=9 as m>0 Now, (r+1) thtermof x2+1xm is  mCrx2m−r1xr=mCrx2m−3rFor this to be independent of x put 2m-3r=0⇒r=6.'. Coefficient of the term independent of x is  9C6=84.