Решите тест за 8 кл пожалуйста

Question 1

Question 2

№1
$\sqrt{81*25} = \sqrt{81} * \sqrt{25} =9*5=45 \\ \\ \sqrt{360} * \sqrt{6,4} = \sqrt{360*6,4} = \sqrt{36*64} = \sqrt{36} * \sqrt{64} =6*8=48 \\ \\ \sqrt{ \frac{45}{125} } = \sqrt{ \frac{9}{25} } = \frac{ \sqrt{9} }{ \sqrt{25} } = \frac{3}{5} \\ \\ 5 \sqrt{ 38^{2} } =5*38=190 \\ \\ \frac{ \sqrt{108}* \sqrt{169} }{ \sqrt{0,48} } = \sqrt{ \frac{108*169}{0,48} } = \sqrt{38025} =195$

№2
$- \sqrt{ \frac{a ^{2}b ^{4} }{169c ^{8} } } = -\sqrt{ \frac{a ^{2}(b ^{2} ) ^{2} }{13 ^{2} } } = -\sqrt{( \frac{ab ^{2} }{13} ) ^{2} } = -\frac{ab ^{2} }{13} \\ \\ \sqrt{ \frac{49a ^{2} }{c ^{12} } } = \sqrt{ \frac{(7a)^{2} }{(c ^{6} ) ^{2} } } = \sqrt{ (\frac{7a}{c ^{6} }) ^{2} } = \frac{7a}{c ^{6} } \\ \\ 0.3 \sqrt{216} -0.8 \sqrt{150} +0.9 \sqrt{6} =0,3 \sqrt{6*36} -0,8 \sqrt{6*25} +0,9 \sqrt{6} = \\ =1,8 \sqrt{6} -4 \sqrt{6} +0,9 \sqrt{6} =-1,3 \sqrt{6} \\$
$(6 \sqrt{2}- \sqrt{13} )( \sqrt{13} +6 \sqrt{2} )=(6 \sqrt{2} ) ^{2} -( \sqrt{13} ) ^{2} =72-13=59 \\ \\ (5 \sqrt{6}-6 \sqrt{2} ) ^{2} =(5 \sqrt{6} ) ^{2} -2*5 \sqrt{6} *6 \sqrt{2} +(6 \sqrt{2} ) ^{2} = \\ \\ =150-60 \sqrt{12} +72=222-120 \sqrt{3} \\$

№3
$7 \sqrt{b} -b \sqrt{7} =( \sqrt{7} ) ^{2} \sqrt{b} -( \sqrt{b} ) ^{2} \sqrt{7} = \sqrt{7} * \sqrt{b}* ( \sqrt{7}- \sqrt{b} )= \\ =\sqrt{7b} *( \sqrt{7}- \sqrt{b} ) \\$
$16-x=4 ^{2} -( \sqrt{x} ) ^{2} =(4- \sqrt{x} )(4+ \sqrt{x} )$