We want to find a simpler form of the given fraction with a binomial denominator. To do it, we will rationalize the fraction by multiplying the numerator and denominator of the fraction by the conjugate of the denominator. We find the conjugate by changing the sign of the second term of the expression.
Binomial
Conjugate
a + b
a - b
a - b
a + b
In this case, the conjugate of the denominator is 3+sqrt(2).