Question

Find the value of a3

+ 8b3 if a+2b=10 and ab =15​

Answer 1

Step-by-step explanation:

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 = 10