`A=(2√2+2+√3+√6)/(1+\sqrt(18)-√8)`
`⇔A=(2(√2+1)+(√2+1)√3)/(1+3√2-2√2)`
`⇔A=((√2 +1)(2+√3))/(1+√2)`
`⇔A=2+√3`
`B=(3√x-21)/(x-9) +2/(√x-3)`
`⇔B=((3√x-21)+2(√x+3))/(x-9) `
`⇔B=(5√x-15)/(x-9) `
`⇔B=(5(√x-3))/((√x-3)(√x+3))`
`⇔B=5/(√x+3)`
khi `B=5/6`
`⇔5/6 =5/(√x+3)`
`⇔√x+3=6`
`⇔√x=3`
`⇔x=9`