a) `\sqrt{49}-\sqrt{36}+2\sqrt{25}`
`=7-6+2.5`
`=1+10`
`=11`
b) `\sqrt{7}+\sqrt{(\sqrt{7}-5)^2}`
`=\sqrt{7}+|\sqrt{7}-5|`
`=\sqrt{7}+5-\sqrt{7}`
`=5`
c) `\sqrt{3}\sqrt{12}+(\sqrt{99})/(\sqrt{11})-3\sqrt{4}`
`=\sqrt{3.12}+\sqrt{(99)/(11)}-3.2`
`=\sqrt{36}+\sqrt{9}-6`
`=6+3-6`
`=3`
d) `2\sqrt{2}+\sqrt{18}-\sqrt{50}+\sqrt{27}`
`=2\sqrt{2}+3\sqrt{2}-5\sqrt{2}+3\sqrt{3}`
`=3\sqrt{3}`
