Đáp án+Giải thích các bước giải:
Bài1:
a/
`(\sqrt5 -\sqrt2)^2+\sqrt40`
`=(\sqrt5)^2-2.\sqrt5 . \sqrt2+(\sqrt2)^2+2\sqrt10`
`=5-2\sqrt10+2+2\sqrt10`
`=7`
b/
`6/(3\sqrt2+2\sqrt3) + (3\sqrt2-3\sqrt6)/(\sqrt3 -1) -\sqrt(2\sqrt3-2021)^2`
`=6/(\sqrt6(\sqrt3+\sqrt2)) +(3\sqrt2(1-\sqrt3))/(\sqrt3-1)-|2\sqrt3-2021|`
`=(\sqrt6)/(\sqrt3+\sqrt2) - 3\sqrt2-(2021-2\sqrt3`
`=(\sqrt6(\sqrt3-\sqrt2))/(3-2)-3\sqrt2+2\sqrt3-2021`
`=\sqrt18-\sqrt12-3\sqrt2+2\sqrt3-2021`
`=3\sqrt2-2\sqrt3-3\sqrt2+2\sqrt3-2021`
`=-2021`
