If x + y = 9 and xy = 20, then find the value of x³ + y³.

Correct option is C

Given:

x + y = 9

xy = 20

Formula Used:

​$$x^3 + y^3 = (x+y)^3 - 3xy(x+y)$$​

Solution:

​$$x^3 + y^3 = (9)^3 - 3(20)(9)$$​

​$$x^3 + y^3 = 729 - 540 = 189$$​