Question

find the value of (a3 - b3 if a - b= 4 and ab = 21)​

Answer 1

Answer:

Given,

a - b = 4,ab = 21

Then,

=(a - b)^3 = a^3 - 3a^2b + 3ab^2 - b^3 =

a^3 - 3ab(a - b) - b^3

=4^3 = a^3 - b^3 - 3(21)(4)

=64 + 252 = a^3 - b^3

a^3 - b^3 = 316  

Hope this helps you...