`d. 2-x/2016-1=1-x/2017-x/2018`
`⇔2-x/2016-1+2=1-x/2017+1-x/2018+1`
`⇔2018-x/2016=2018-x/2017-x+2018/2018`
`⇔(2018-x)(1/2016-1/2017+1/2018)=0`
`⇔2018-x=0 (vì 1/2016-1/2017+1/2018` $\neq$ `0)`
`⇔x=2018`
`e.x²+6x+9=144`
`<=> (x-3)^2 =144`
`<=> x-3=±12`
`+) x-3=12`
`=> x=15`
`+) x-3=-12`
`=>x=-9`
`<=> x=15` hoặc `x=-9`
`f. x^3 - 3x^2 + 4 =0`
`<=> (x^3 + 1) - (3x^2 - 3 ) =0`
`<=> (x+1)(x^2 - x +1 ) - 3 (x-1)(x +1) =0`
`<=> (x +1)(x^2 - 4x +4) =0`
`<=> (x +1)(x -2)^2 =0`
`<=> x =-1` hoặc `x =2`
$army×blink$
