Решите пожалуйста. √32+√18-√50; (7√8-√98+√10)√2; (√5-√18)(√5-2√2)

$\sqrt{32} + \sqrt{18} - \sqrt{50} = \sqrt{16*2} + \sqrt{9*2} - \sqrt{25*2} =$ $4 \sqrt{2} +3 \sqrt{2} - 5\sqrt{2} = 2\sqrt{2}$
$(7 \sqrt{8} - \sqrt{98} + \sqrt{10} ) \sqrt{2} =(7 \sqrt{4*2} - \sqrt{49*2} + \sqrt{4*2.5} ) \sqrt{2} =$ $(14 \sqrt{2} -7 \sqrt{2} + 2\sqrt{2.5} ) \sqrt{2} =(7 \sqrt{2} + 2\sqrt{2.5} ) \sqrt{2} =7*2+2\sqrt{2.5*2}$ = $14+2\sqrt{5}$
$( \sqrt{5} - \sqrt{18} ) ( \sqrt{5} -2 \sqrt{2} )=$ $\sqrt{5} *\sqrt{5} - \sqrt{18} *\sqrt{5} -\sqrt{5}*2 \sqrt{2} +2 \sqrt{2} *\sqrt{18} =$ $5+ \sqrt{9*2*2} -2 \sqrt{10} +2 \sqrt{36} =5+6-2 \sqrt{10} +12=23-2 \sqrt{10}$