`f)` `2\sqrt{18}-\sqrt{27}-\sqrt{48}+2\sqrt{98}`
`=2.\sqrt{2. 3^2}-\sqrt{3^2 .3}-\sqrt{4^2 .3}+2\sqrt{7^2 . 2}`
`=2.3\sqrt{2}-3\sqrt{3}-4\sqrt{3}+2.7\sqrt{2}`
`=6\sqrt{2}+14\sqrt{2}-(3\sqrt{3}+4\sqrt{3})`
`=20\sqrt{2}-7\sqrt{3}`
$\\$
`g)` `\sqrt{2}-\sqrt{8}+\sqrt{50}`
`=\sqrt{2}-\sqrt{2^2 . 2}+\sqrt{5^2 . 2}`
`=\sqrt{2}-2\sqrt{2}+5\sqrt{2}`
`=4\sqrt{2}`
$\\$
`h)` `\sqrt{12}-3\sqrt{18}-2\sqrt{27}+\sqrt{32}`
`=\sqrt{2^2 . 3}-3\sqrt{3^2 . 2}-2\sqrt{3^2 . 3}+\sqrt{4^2 . 2}`
`=2\sqrt{3}-3.3\sqrt{2}-2.3\sqrt{3}+4\sqrt{2}`
`=2\sqrt{3}-6\sqrt{3}+4\sqrt{2}-9\sqrt{2}`
`=-4\sqrt{3}-5\sqrt{2}`
$\\$
`i)` `\sqrt{20}-\sqrt{45}+3\sqrt{18}+\sqrt{72}`
`=\sqrt{2^2 . 5}-\sqrt{3^2 . 5}+3\sqrt{3^2 . 2}+\sqrt{6^2 . 2}`
`=2\sqrt{5}-3\sqrt{5}+3.3\sqrt{2}+6\sqrt{2}`
`=-\sqrt{5}+15\sqrt{2}`
