Đáp án+Giải thích các bước giải:
`x=2/(2+sqrt3)`
`=(2(2-sqrt3))/(2+sqrt3)`
`=4-2sqrt3`
`=(sqrt3-1)^2`
`=>sqrtx=sqrt3-1`
`=>P=(4-2sqrt3)/(sqrt3-1-1)`
`=(4-2sqrt3)/(sqrt3-2)`
`=(2(2-sqrt3))/(sqrt3-2)=-2`
`b)P=(sqrtx+1)/(sqrtx-2)`
`=(sqrtx-2+3)/(sqrtx-2)`
`=1+3/(sqrtx-2)`
`x=(3-sqrt5)/2=(6-2sqrt5)/4`
`=(sqrt5-1)^2/2`
`=>sqrtx=(sqrt5-1)/2`
`=>P=1+3/((sqrt5-1)/2-2)`
`=1+6/(sqrt5-5)`
`=1+(6(5+sqrt5))/(5-25)`
`=1+(6(5+sqrt5))/(-20)`
`=1-(30-6sqrt5)/20`
`=(-10-6sqrt5)/20`
`=(-5-3sqrt5)/10`.
