a)
\sqrt{12}*\sqrt3=\sqrt{36}=6
b)
\sqrt{32}*\sqrt8=\sqrt{32*8}=\sqrt{256}=16
c)
\sqrt{10}*\sqrt{40}=\sqrt{400}=\sqrt{20^2}=20
d)
\sqrt{18}*\sqrt{50}=\sqrt{900}=\sqrt{30^2}=30
albo
\sqrt{18}*\sqrt{50}=\sqrt{9}*\sqrt2*\sqrt{50}=3\sqrt{100}=3*10=30
e)
\sqrt{28}*\sqrt{63}=\sqrt{4*7}*\sqrt{9*7}=2\sqrt7*3\sqrt7=6*(\sqrt7)^2=6*7=42
f)
\sqrt{45}*\sqrt{20}=\sqrt{45*20}=\sqrt{900}=\sqrt{30^2}=30