# How do you rationalize the denominator and simplify 1/sqrt7?

1/sqrt7=(1·sqrt7)/(sqrt7·sqrt7)=sqrt7/7
In a fraction if we multiply and divide by the same number, the fraction doesn't varies. We choose $\sqrt{7}$ because we need to remove saquare root from denominator and we know that
sqrta·sqrta=sqrt(a^2)=a for whatever be $a \in \mathbb{R}$