Помогите с алгеброй пж

1.
$11 \sqrt{5} + 10 \sqrt{5} - 6 \sqrt{5} = 15 \sqrt{5}$
2.
$3 \times 5 \times 2 - 3 \times \sqrt{64} = \\ 30 - 3 \times 8 = 6$
3.
$6 + 2 \sqrt{6 \times 3} + 3 = 9 + 2 \sqrt{18} = \\ 9 + 2 \times 3 \sqrt{2} = 9 + 6 \sqrt{2}$
4.
${ \sqrt{3} }^{2} - { \sqrt{8} }^{2} = 3 - 8 = - 5$
5.
$\frac{ \sqrt{7}( \sqrt{7} + 1) }{5 \sqrt{7} } = \frac{ \sqrt{7} + 1}{5}$
7.
$\sqrt{9 + 2 \times 3 \times \sqrt{3} + 3} = \\ \sqrt{ {(3 + \sqrt{3}) }^{2} } = 3 + \sqrt{3}$