Đáp án+Giải thích các bước giải:
`a)\sqrt{1/7}+1/7sqrt{28}-sqrt{(sqrt7-3)^2}`
`=1/sqrt7+(2sqrt7)/7-(3-sqrt7)`
`=sqrt7/7+(2sqrt7)/7-3+sqrt7`
`=(3sqrt7+7sqrt7-21)/7`
`=(10sqrt7-21)/7`
`c)((3sqrt2-sqrt6)/(sqrt{12}-2)-sqrt{294}/2)*1/sqrt6`
`=((sqrt{6}(sqrt2-1))/(2(sqrt3-1))-(7sqrt6)/2)*1/sqrt6`
`=(sqrt2-1)/(sqrt3-1)-7/2`
`=((sqrt2-1)(sqrt3+1))/(3-1)-7/2`
`=(sqrt6+sqrt2-sqrt3-1)/2-7/2`
`=(sqrt6+sqrt2-sqrt3-8)/2`
`e)(1/(2sqrt5-sqrt3)+1/(2sqrt5+sqrt3)):(sqrt3+1)/17`
`=((2sqrt5+sqrt3)/(20-3)+(2sqrt5-sqrt3)/(20-3))*17/(sqrt3+1)`
`=(2sqrt5+sqrt3+2sqrt5-sqrt33)/17*17/(sqrt3+1)`
`=(4sqrt5)/(sqrt3+1)`
`=(4sqrt5(sqrt3-1))/(3-1)`
`=2sqrt5(sqrt3-1)=2sqrt{15}-2sqrt5`
