Find the Value

\[ a+b=10 \]

\[ ab=21 \]

Find:

\[ a^3+b^3 \]

Solution:

Using identity:

\[ a^3+b^3=(a+b)^3-3ab(a+b) \]

\[ a^3+b^3 = (10)^3-3(21)(10) \]

\[ = 1000-630 \]

\[ =370 \]

Next Question / Full Exercise