Question

If x=3+2root2, find x3+1/x3

Answer 1

Step-by-step explanation:

x=3+2√2=(√2+1)²

x³+1/x³

=(√2+1)^6+(√2-1)^6

Answer 2

Answer:

198

Step-by-step explanation:

x=3+2√2

1/x=1/3+2√2

      =(3-2√2)/(3+2√2)(3-2√2)

      =(3-2√2)/3²-(2√2)²

       =(3-2√2)/9-8

       =3-2√2

x³+1/x³=(x+1/x)³-3(x+1/x)

            =(3+2√2+3-2√2)³-3(3+2√2+3-2√2)

            =6³-3(6)

            =216-18

             =198