Question

If a + b = 10 and ab = 15, find the value of a3 + b3​

Answer 1

Answer:

550

Step-by-step explanation:

(a+b)³= a³+b³+3ab (a+b)

10³=a³+b³+3×15 (10). [given in ques]

1000=a³+b³+450

a³+b³=1000-450

a³+b³=550

hope it will help you.

Answer 2

Answer:

Given a +2b = 10 and ab = 15 Consider, a3 + 8b3 = a3 + (2b)3 = (a + 2b)3 − 3 × a × 2b(a + 2b) [Since, a3 + b3 = (a + b)− 3ab(a + b)] = (a + 2b)3 − 6ab(a + 2b) = (10)3 − 6 × 15 × 10 = 1000 − 900 = 100