Question

If x = 3+√8
find the value of x3+1/x3

Answer 1

Answer:198

Step-by-step explanation:

x=3+√8

x=3+2√2

x^3=(3+2√2)^3

    =27+16√2+3(3)(2√2)(3+2√2)

    =27+16√2+18√2(3+2√2)

    =27+16√2+54√2+72

    =99+70√2

1/x^3=99-70√2

x^3+1/x^3=(99+70√2)+(99-70√2)

               =198