if (1+ax +bx2)(1-2x)18 be expressed in ascending powers of x such that coefficient of x3 and x4 are 0 then (a,b)is equal to :
a) (16,272/3) b) (4,44/3)
c)(1/16,88/3)
The given expression can be express by binomial theorem as follow
It is given that the coefficients of are zero. Therefore we have
Now, we will add the equation (1) and equation (2), we get
From equation (2), we have
Hence, the correct option is (a )