Question 143486
(a-b)^5 = 5C5a^5 + 5C4a^4(-b) + 5C3a^3(-b)^2 + 5C2a^2(-b)^3 + 5C1a(-b)^4+ (-b)^5

= a^5 -5a^4b + 10a^3b^2 -10a^2b^3 +5ab^4 -b^5
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Cheers,
Stan H.