If the sum of the coefficients in the expansion (1+x−3x2)171 is
A
−3171
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B
1
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C
2171
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D
−1
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Solution
The correct option is B−1 (1+x−3x2)171 =a0+a1x+a2x2... ...(i) To get the sum of the coefficients we substitute x=1 in (i) Hence, we get a0+a1+a2... =(1+1−3(1)2)171 =(−1)171 Since 171 is odd, sum of coefficients=(−1)171=−1