Introducerea factorilor sub radical

$$\begin{gathered} a, b\in \mathrm{ℝ}, b\ge 0 \\ a\sqrt{b}=\left\{\begin{array}{l} \sqrt{a^{2}b}, a\ge 0\\ -\sqrt{a^{2}b}, a<0\end{array}\right. \end{gathered}$$

Exemple:

$$\begin{gathered} 7\sqrt{2}=\sqrt{7^2·2}=\sqrt{98} \\ -6\sqrt{3}=-\sqrt{(-6{)}^2·3}=-\sqrt{108}. \end{gathered}$$