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Let a and b with a > b > 0 be real numbers satisfying a^3 + b^3 = a + b. Find (a+b)21ab .

 Jun 21, 2021
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Let a and b with a > b > 0 be real numbers satisfying a3+b3=a+b.
Find (a+b)21ab.

 

Formula:a3+b3=(a+b)(a2ab+b2)

 

a3+b3=(a+b)(a2ab+b2)|a3+b3=a+b(a+b)=(a+b)(a2ab+b2)a2ab+b2=a+ba+ba2ab+b2=1a2+b2ab=1|a2+b2=(a+b)22ab(a+b)22abab=1(a+b)23ab=1(a+b)21=3ab|:ab(a+b)21ab=3

 

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 Jun 21, 2021

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