Đáp án:
`ĐK:x>=0,x ne 9`
`a)x=11-6sqrt2`
`=9-2.3.sqrt2+2`
`=(3-sqrt2)^2(tmđk)`
`=>B=3/(sqrt{(3-sqrt2)^2}-3)`
`=3/(3-sqrt2-3)=3/(-sqrt2)=(-3sqrt2)/2`
`b)A=(2sqrtx)/(x-9)+1/(sqrtx-3)`
`=(2sqrtx)/(x-9)+(sqrtx+3)/(x-9)`
`=(3sqrtx+3)/(x-9)`
`=>P=B:A=(3sqrtx+3)/(x-9):3/(sqrtx-3)`
`=(3(sqrtx+1))/((sqrtx-3)(sqrtx+3))*(sqrtx+3)/3`
`=(sqrtx+1)/(sqrtx-3)`
`c)P=3/2`
`<=>(sqrtx+1)/(sqrtx-3)=3/2`
`<=>2sqrtx+2=3sqrtx-9`
`<=>2+9=3sqrtx-2sqrtx`
`<=>11=sqrtx`
`<=>x=121(tm)`
`d)P in ZZ`
`=>sqrtx+1 vdots sqrtx-3`
`=>sqrtx-3+4 vdots sqrtx-3`
`=>4 vdots sqrtx-3`
`=>sqrtx-3 in Ư(4)={+-1,+-4}`
`=>sqrtx in {4,2,7}`
`=>x in {4;16;49}`