`a) 8x(x-8)-x+8=0`
`<=> 8x(x-8)-(x-8)=0`
`<=> (x-8)(8x-1)=0`
`<=> [(x-8=0),(8x-1=0):}`
`<=>`\(\left[ \begin{array}{l}x=8\\x=\dfrac{1}{8}\end{array} \right.\)
Vậy `S={8;1/8}`
`b) x^3-13x=0`
`<=> x(x^2-13)=0`
`<=> x(x-\sqrt{13})(x+\sqrt{13})=0`
`<=>[(x=0),(x-\sqrt{13}=0),(x+\sqrt{13}=0):}`
`<=> [(x=0),(x=\sqrt{13}),(x=-\sqrt{13}):}`
Vậy `S={0;+-sqrt{13}}`
`c) x+5x^2=0`
`<=> x(1+5x)=0`
`<=> [(x=0),(1+5x=0):}`
`<=>`\(\left[ \begin{array}{l}x=0\\x=\dfrac{-1}{5}\end{array} \right.\)
Vậy `S={0;-1/5}`
`d) (x+1)=(x+1)^2`
`<=> (x+1)^2-(x+1)=0`
`<=> (x+1)(x+1-1)=0`
`<=> x(x+1)=0`
`<=> [(x=0),(x+1=0):}`
`<=> [(x=0),(x=-1):}`
Vậy `S={0;-1}`
`e) x^3+x=0`
`<=> x(x^2+1)=0`
`=> x=0` (do `x^2+1>0` với `AAx`)
Vậy `S={0}`
`f) x(x-2022)-2021(2022-x)=0`
`<=> x(x-2022)+2021(x-2022)=0`
`<=> (x-2022)(x+2021)=0`
`<=> [(x-2022=0),(x+2021=0):}`
`<=> [(x=2022),(x=-2021):}`
Vậy `S={2022;-2021}`
