Question

If a + b =5 and ab = 6 find$a^3+b^3$

• A. 38
• B. 37
• C. 36
• D. 35

Answer 1

Answer:

D. 35

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

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

$=5^3-3\times6(5)$

$=125-90$

$=35$