Đáp án:
Giải thích các bước giải:
`a)4x-(x+5)=2x-7`
`↔4x-x-5=2x-7`
`↔3x-5=2x-7`
`↔3x-2x=-7+5`
`↔x=-2`
Vậy `S={-2}`
`b)3x-4(2x-5)=3x-5`
`↔3x-8x+20=3x-5`
`↔-8x=-25`
`↔x=26/8`
Vậy `S={26/8}`
`c)(6x+1)/4 - (3x+2)/3 =(5x-1)/6 + 1/2`
`↔(3(6x+1))/12+(4(-3x+2))/12=(2(5x-1))/12+6/12`
`↔18x+2-12x+8=10x-2+6`
`↔-4x=-6`
`↔x=3/2`
Vậy `S={3/2}`
`d)(3x-7)/2-(6x+5)/4=(2x-1)/4+5`
`↔(2(3x-7)-6x+5)/4=(2x-1+20)/4
`↔6x-14-6x+5=2x-1+20`
`↔-2x=28`
`↔x=-14`
Vậy `S={-14}`
`e)(4x-5)(2x+1)(x-3)=0`
`↔` \(\left[ \begin{array}{l}x=\dfrac{5}{4}\\x=-\dfrac{1}{2}\\x=3\end{array} \right.\)
Vậy `S={5/4;-1/2;3}`
`f)3x(x-5)-7(x-5)=0`
`↔(3x-7)(x-5)=0`
`↔` \(\left[ \begin{array}{l}x=\dfrac{7}{3}\\x=5\end{array} \right.\)
Vậy `S={7/3;5}`
`g)3x+2-6x-4=0`
`↔-3x-2=0`
`↔-3x=2↔x=-2/3`
Vậy `S={-2/3}`
`h)x^2-4+2(x-2)=0`
`↔(x-2)(x+2)+2(x-2)=0`
`↔(x-2)(x+2+2)=0`
`↔(x-2)(x+4)=0`
`↔` \(\left[ \begin{array}{l}x=2\\x=-4\end{array} \right.\)
Vậy `S={2;-4}`
