`a)A=\sqrt{0,1}+\sqrt{0,9}+\sqrt{6,4}+\sqrt{0,4}+\sqrt{44,1}`
`A=\sqrt{1/10}+\sqrt{9/10}+\sqrt{64/10}+\sqrt{4/10}+\sqrt{441/10}`
`A=1/\sqrt{10}+3/\sqrt{10}+8/\sqrt{10}+2/\sqrt{10}+21/\sqrt{10}`
`A=[1+3+8+2+21]/\sqrt{10}=35/\sqrt{10}`
`A=[35\sqrt{10}]/10`
