Question

If x minus y equal to 16 and xy equal to 14 then find the value of x cube minus y cube

Answer 1

(x - y)² = x² + y² - 2xy

16²  = x² + y² - 2x14

256 = x² + y² - 28

x² + y² = 284  -------------(1)

x³ - y³ = (x - y) (x² + y² + ab)

          = 16(284 + 14)

           = 16(298

x³ - y³ = 4768