Đáp án + Giải thích các bước giải:
`1)` `4x(x-5)-(x-1)(4x-3)=5`
`<=>4x^2-20x-(4x^2-3x-4x+3)=5`
`<=>4x^2-20x-4x^2+3x+4x-3=5`
`<=>-13x=8`
`<=>x=-8/13`
Vậy `S={-8/13}`
`2)` `(3x-4)(x-2)=3x(x-9)-3`
`<=>3x^2-6x-4x+8=3x^2-27x-3`
`<=>3x^2-6x-4x+8-3x^2+27x+3=0`
`<=>17x+11=0`
`<=>17x=-11`
`<=>x=-11/17`
Vậy `S = {-11/17}`
`3)` `(x-5)(x-4)-(x+1)(x-2)=7`
`<=>x^2-9x+20-(x^2-2x+x-2)=7`
`<=>x^2-9x+20-x^2+2x-x+2=7`
`<=>-8x+22=7`
`<=>-8x=-15`
`<=>x=15/8`
Vậy `S={15/8}`
`4)` `5x(x-3)=(x-2)(5x-1)-5`
`<=>5x^2-15x=5x^2-x-10x+2-5`
`<=>5x^2-15x-5x^2+x+10x-2+5=0`
`<=>-4x+3=0`
`<=>-4x=-3`
`<=>x=3/4`
Vậy `S={3/4}`.
