[tex] \sqrt{3 \sqrt{36} + 7} - 8 \sqrt{0.25} + \sqrt{ {20}^{2} - {16}^{2} } [/tex]
[tex] = \sqrt{3 \times 6 + 7} - 8 \sqrt{ \frac{25}{100} } + \sqrt{(20 - 16)(20 + 16)} [/tex]
[tex] = \sqrt{18 + 7} - 8 \times \frac{ \sqrt{25} }{ \sqrt{100} } + \sqrt{4 \times 36} [/tex]
[tex] = \sqrt{25} - 8 \times \frac{ 5 }{10} + \sqrt{4} \times \sqrt{36} [/tex]
[tex] = 5 - 8 \times \frac{1}{2} + 2 \times 6[/tex]
[tex] = 5 - \frac{8}{2} + 12[/tex]
[tex] = 5 - 4 + 12[/tex]
[tex] = 1 + 12[/tex]
[tex] = 13[/tex]
