Question

Find the value of a3 + 8b3 , if a +2b = 10 and ab = 15.

Answer 1

(a+2b)^3=1000
=>a^3+8b^3+6a^2b+12ab>2=1000
=>a^3+8b^3+6ab(a+2b)=1000
=>a^3+8b^3+6×15×10=1000
=>a^3+8b^3=100

Answer 2

Answer:

The value of a³+8b³ is 100.

Step-by-step explanation:

• In context to the given question, we have to find the value of the given problem;

Given;

a + 2b = 10

ab = 15

To find :

a³+ 8b³

Solution:

We know that,

(a+ b)³ =a³+b³+3a²b+3ab²

(a+2b)³=(10)³=1000

=>a³+8b³+6a²b+12ab²=1000  [ by applying identity]

=>a³+8b³+6ab(a+2b)=1000    

=>a³+8b³+6(15)(10)=1000        [ by putting value]

=>a³+8b³=100

Therefore, the value of a³+8b³ is 100.