What is the sum of all real roots of the equation If you think there is no real root, submit 99999 as your answer.
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Let a = 3 x + 4 5 and b = 3 1 6 − x .
Then you'll see that
a 3 + b 3 = 6 1 and a + b = 1
Since ( a + b ) 3 = a 3 + b 3 + 3 a b ( a + b ) ,
a + b = 1 and a b = − 2 0
Therefore a = 5 or a = − 4 .
Substituting to the definition of a , we get:
x = 8 0 or x = − 1 0 9 .
Since 3 1 2 5 + 3 − 6 4 = 1 ,
The sum of all real roots of the given equation is − 2 9 .