helppppppppppppppppppppppppppppppppppppppppppppppppppppppppp

Đáp án+Giải thích các bước giải:

`a)4(x+2)-1=x-5`

`<=>4x+8-1=x-5`

`<=>4x+7=x-5`

`<=>x-4x=5+7`

`<=>-3x=12`

`<=>x=-4`

Vậy `S={-4}`

`b)(x-2)(2x-1)=5(x-2)`

`<=>(x-2)(2x-1)-5(x-2)=0`

`<=>(x-2)(2x-1-5)=0`

`<=>(x-2)(2x-6)=0`

`<=>2(x-2)(x-3)=0`

`<=>(x-2)(x-3)=0`

`<=>` \(\left[ \begin{array}{l}x-2=0\\x-3=0\end{array} \right.\) 

`<=>` \(\left[ \begin{array}{l}x=2\\x=3\end{array} \right.\) 

Vậy `S={2;3}`

`c)(x+5)/(x-5)-(x-5)/(x+5)=(x(x+25))/(x^2 -25)`

`ĐKXĐ:x\ne +-5`

`<=>((x+5)^2)/((x-5)(x+5))-((x-5)^2)/((x+5)(x-5))=(x^2 +25x)/((x-5)(x+5))`

`=>x^2 +10x+25-x^2 +10x-25=x^2 +25x`

`<=>20x=x^2 +25x`

`<=>x^2 +25x-20x=0`

`<=>x^2 +5x=0`

`<=>x(x+5)=0`

`<=>` \(\left[ \begin{array}{l}x=0\\x+5=0\end{array} \right.\) 

`<=>` \(\left[ \begin{array}{l}x=0(tm)\\x=-5(ktm)\end{array} \right.\) 

Vậy `S={0}`