X=√2+1
X^2=3+2√2
X^3=(3+2√2)( √2+1)
=3√2+3+4+2√2
=5√2+7
X^3-x-6
=5√2+7-√2-1-6
=4√2
log(x*3-x-6)
=log(4√2 )
=log2^5/2
=5/2log2