[tex]7\sqrt{10} = \sqrt{7 * 7 * 10} = \sqrt{490}[/tex]
[tex]\frac{2}{3}\sqrt{90} = \sqrt{90 * \frac{2}{3}*\frac{2}{3}} = \sqrt{40}[/tex]
[tex]\sqrt{600} = \sqrt{100 * 6} = 10\sqrt{6}[/tex]
[tex]\sqrt{98} = \sqrt{49*2} = 7\sqrt{2}[/tex]
:)
