What is the fifth term in the binomial expansion of open paren x plus 5 close paren to the 8th power ?

In the expansion of (x + 5)^8, the term in position r + 1 is [8 choose r]x^(8-r)5^r. For the fifth term, r = 4, so the term is [8 choose 4]x^4(5^4) = 70 · 625x^4 = 43,750x^4. Therefore, the fifth term is 43,750x to the fourth power, choice D.

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