Đáp án:
`g)\sqrt{9-4sqrt5}=sqrt{5-2.2.sqrt5+4}=sqrt{(sqrt5-2)^2}=sqrt5-2` $\\$ `h)sqrt{7+4sqrt3}=sqrt{4+2.2.sqrt3+3}=sqrt{(2+sqrt3)^2}=2+sqrt3` $\\$ `i)sqrt{8+2sqrt{15}}=sqrt{3+2.sqrt3.sqrt5+5}=sqrt{(sqrt5+sqrt3)^2}=sqrt5+sqrt3` $\\$ `k)sqrt{9-2sqrt{14}}=sqrt{7-2.sqrt2.sqrt7+2}=sqrt{(sqrt7-sqrt2)^2}=sqrt7-sqrt2` $\\$ `l)sqrt{14-6sqrt5}=\sqrt{9-2.3.sqrt5+5}=sqrt{(3-sqrt5)^2}=3-sqrt5`