a) [tex]...=8 \sqrt{18} =24 \sqrt{2} [/tex]
b) 3.
c) [tex]...=10 \sqrt{90} :(15 \sqrt{5} )=30 \sqrt{10} :(15 \sqrt{5} )=2 \sqrt{2} [/tex]
d)[tex]...=2 \sqrt{10} -3\sqrt{10} +12\sqrt{10} -20\sqrt{10} =-9\sqrt{10} [/tex]
e)[tex]...=8 \sqrt{2} +4 \sqrt{5}-8 \sqrt{2}-3 \sqrt{5} = \sqrt{5} [/tex]