Đáp án:
`1)3/5(4-5x)-4/3(1-6x)=10x+1`
`<=>3/5*4-3/5*5x-4/3+4/3*6x=10x+1`
`<=>12/5-3x-4/3+8x=10x+1`
`<=>5x+16/15=10x+1`
`<=>10x-5x=16/15-1`
`<=>5x=1/15`
`<=>x=1/75`
Vậy pt có nghiệm duy nhất `x=1/75`
`2)(1-3x)^2021=(3x-1)^2019`
`<=>(3x-1)^2019-(1-3x)^2021=0`
`<=>(3x-1)^2019+(3x-1)^2021=0`
`<=>(3x-1)^2019[1+(3x-1)^2]=0`
Vì `(3x-1)^2>=0`
`=>(3x-1)^2+1>=1>0`
`=>(3x-1)^2019=0`
`<=>3x-1=0`
`<=>3x=1`
`<=>x=1/3`
Vậy py có nghiệm duy nhất `x=1/3.`
