The question requires us to divide 1 by (√3 − √2).
We need to multiply top and bottom of the fraction by the conjugate of (√3 − √2).
The conjugate is easily found by reversing the sign in the middle of the radical expression. In this case, our minus becomes plus. So the conjugate of (√3 − √2) is (√3 + √2).

After we multiply top and bottom by the conjugate, we see that the denominator becomes free of radicals (in this case, the denominator has value 1).