Đáp án + Giải thích các bước giải:
`120/x=120(x-6)-2/3(x ne 0)`
`<=>120/x-120(x-6)+2/3=0`
`<=>(120*3)/(3x)-[120*3x(x-6)]/(3x)+(2x)/(3x)=0`
`=>360-360x(x-6)+2x=0`
`<=>360-360x^2+2160x+2x=0`
`<=>-360x^2+2162x+360=0`
`<=>-180x^2+1081x+180=0`
Ta có : `Delta=b^2-4ac=1081^2-4(-180)*180`
`=1168561+129600=1298161>0`
`=>sqrtDelta=sqrt1298161`
Do đó `x_1=(-b+sqrtDelta)/(2a)=(-1081+sqrt1298161)/-360=[-(-1081+sqrt1298161)]/360`
`=(1081-sqrt1298161)/360(tm)`
`x_2=(-b-sqrtDelta)/(2a)=(-1081-sqrt1298161)/(-360)=[-(-1081-sqrt1298161)]/360`
`=(1081+sqrt1298161)/360(tm)`
Vậy `x_1=(1081-sqrt1298161)/360,x_2=(1081+sqrt1298161)/360`.