Question

If a + b =10 and ab = 16 find$a^3+b^3$

• A. 480
• B. 520
• C. 680
• D. 720

Answer 1

Answer:

B. 520

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

$a^3+b^3=(a+b)^3-3ab(a+b)$

$=10^3-3\times16(10)$

$=1000-480$

$=520$