Question

x=2^1\3=2^-1/3,prove 2x^3=6x+5

Answer 1

Answer:

done below for you

Step-by-step explanation:

Let the cube root of 2 be y.

=>x = y + 1/y

=>2x^3 = 2(y + 1/y)^3

            = 2(y^3 + 1/y^3 + 3y + 3/y)

            = 2(y^3 + 1/y^3) + 6(y + 1/y)

Note that y^3 = 2.

=> 2x^3 = 2(2 + 1/2) + 6x                              (y + 1/y = x as mentioned above)

             = 5 + 6x