The following list gives the coefficients for the binomial expansion of open paren x plus y close paren to the 10th power What is the value of cap b ? 1 , 10 , 45 , 120 , 210 , 252 , 210 , cap b , 45 , 10 , 1

The coefficients in the expansion of (x + y)^10 are the entries in row 10 of Pascal’s triangle. They are symmetric from the beginning to the end, so the missing coefficient after 210 matches the earlier 120; therefore, b = 120, choice A.

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