a+b = 11

a^2+b^2=99

=>

(a+b)^2 = a^2+b^2+2ab

121=99+2ab

or

ab=11

Now lets look at

(a+b)(a^2+b^2) = a^3+ab(a+b)+b^3

11*99 = a^3+b^3+11*11

**a^3+b^3 = 968**

+1 vote

If the sum of two numbers is 11, and the sum of their squares is 99, find the sum of their cubes.

+1 vote

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