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)


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 )

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