Đáp án+Giải thích các bước giải:
`1)C=(sqrtx+2)/(sqrtx-3)(x>=0,x ne 9)`
`x=1/25`
`=>sqrtx=1/5`
`=>C=(1/5+2)/(1/5-3)`
`=>C=(11/5)/(-14/5)`
`=>C=-11/14`
Vậy `x=1/25` thì `C=-11/14.`
`2)C=-2`
`<=>(sqrtx+2)/(sqrtx-3)=-2`
`<=>sqrtx+2=6-2sqrtx`
`<=>3sqrtx=4`
`<=>sqrtx=4/3`
`<=>x=16/9(tm)`
`C=7/5`
`<=>(sqrtx+2)/(sqrtx-3)=7/5`
`<=>5sqrtx+10=7sqrtx-21`
`<=>2sqrtx=31`
`<=>sqrtx=31/2`
`<=>x=961/4(tm)`
`3)C>1`
`<=>(sqrtx+2)/(sqrtx-3)-1>0`
`<=>(sqrtx+2-sqrtx+3)/(sqrtx-3)>0`
`<=>5/(sqrtx-3)>0`
Mà `5>0`
`<=>sqrtx-3>0`
`<=>sqrtx>3`
`<=>x>9`
`B<=-7/2`
`<=>B+7/2<=0`
`<=>(sqrtx+2)/(sqrtx-3)+7/2<=0`
`<=>(2sqrtx+4+7sqrtx-21)/(2(sqrtx-3))<=0`
`<=>(9sqrtx-17)/(2(sqrtx-3))<=0`
Mà `9/2>0`
`<=>(sqrtx-17/9)/(sqrtx-3)<=0`
Mà `sqrtx-17/9>sqrtx-3`
`<=>{(sqrtx-17/9>=0),(sqrtx-3<0):}`
`<=>288/81<=x<9`
