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If the coefficients of x 3 and x 4 in the expansion of (1 + ax + bx 2 ) (1 – 2x) 18 in powers of x are both zero, then (a, b) is equal to :

1.       3 272 , 16
2.       3 251 , 16
3.       3 251 , 14
4.       3 272 , 14

Correct answer:       3 272 , 16

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