Question

If x=2/3+√7,then(x-3)^3 is

Answer 1

Given that,
x=2/(3+√7)

x=2/(3+√7)×(3-√7)/(3-√7)

x=2(3-√7)/(9-7)

x=3-√7

Now,
(x-3)^3=(3-√7-3)^3
=(-√7)^3
=(-√7)^2×(-√7)
=7(-√7)
=-7√7

Hence (x-3)^3=-7√7