If $$a^3-b^3=416$$ and $$a-b=8$$, then $$(a+b)^2-ab$$ is equal to:
$$(a^3-b^3)=(a-b)(a^2+ab+b^2)$$
So,$$(a^2+ab+b^2)=416\div 8=52.$$
C is correct choice.
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