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Bunuel
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Maheshkv
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Raulperez947
Maheshkv
The sum of two numbers is 1 and their product is -1. What is the sum of their cubes?

A. 1
B. 2
C. 3
D. 4
E. 5

(a+b)^3= a^3+ 3*ab*(a+b)+b^3

substituting the values of a+b and ab would give us the required answer of a^3+b^3


why are you using the formula for (a+b)^3 if they are asking for the sum of x^3 + y^3? I'm not sure if i'm correct


Given:
    \(a + b = 1\)


Taking to the third power gives:
    \((a + b)^3 = 1^3\)
    \(a^3 + 3ab(a + b) + b^3 = 1\)

Since given that a + b = 1 and ab = -1, then substituting these into the above gives:
    \(a^3 - 3 + b^3 = 1\)
    \(a^3 + b^3 = 4\)

Answer: D.

Hope it's clear.
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Thank you!! it's clear
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