Question

If (2a + b ) = 15 and ab = - 8 ,then find the value of 8a3 + b3​

Answer 1

Answer:

Given:

2a + b = 15 and ab = -8

Find:

value of (8a³+b³)

Now,

(2a+b)³ = 8a³+b³+6ab(2a+b)

(15)³ = 8a³+ b³ +6(-8)(15)

3375 = 8a³+ b³ -720

8a³+ b³ = 3375+720 = 4095