Question

If a+b=4 and ab=3 find the value of a³+b³

Answer 1

Given:-

a+b=4

ab=3

To find:-

Value of a³+b³

Solution:-

We know that (a+b)³=a³+b³+3ab(a+b)

So,by cubing both the sides in equation a+b=4,we get-----

(a+b)³=(4)³

=>a³+b³+3ab(a+b)=64

Now,by substituting the values of ab and a+b,we get----

=>a³+b³+3×3(4)=64

=>a³+b³+36=64

=>a³+b³=64-36

=>a³+b³=28

Thus,the value of a³+b³ is 28.