Question

x = 3√ab - 3√1/ab . prove that : x3 + 3x = ab - 1/ ab​

Answer 1

Answer:

Let y^3=ab, then x=y-1/y; x^3=y^3-3y^2/y+3y/y^2-1/y^3=y^3-3y+3/y-1/y^3.

Let y^3=ab, then x=y-1/y; x^3=y^3-3y^2/y+3y/y^2-1/y^3=y^3-3y+3/y-1/y^3.3x=3y-3/y; so x^3=y^3-3x-1/y^3 and x^3+3x=y^3-1/y^3=(ab)-1/(ab) QED

Step-by-step explanation:

just like that