Question

a,(2x-3)^2-(2x+1)(2x-1)=2 b,(3x-1)(x+2)-(x-1)^2=x-3 c, x^2-8x+7=0 helpppppp

Answer 1

`a)(2x-3)^2-(2x+1)(2x-1)=2`

`<=>4x^2-12x+9-4x^2+1=2`

`<=>-12x=-8`

`<=>x=2/3`

Vậy `S={2/3}`

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`b)(3x-1)(x+2)-(x-1)^2=x-3`

`<=>3x^2+6x-x-2-x^2+2x-1-x+3=0`

`<=>2x^2+6x=0`

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

`<=>[(2x=0),(x+3=0):}`

`<=>[(x=0),(x=-3):}`

Vậy `S={0;-3}`

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`c)x^2-8x+7=0`

`<=>x^2-7x-x+7=0`

`<=>(x-7)(x-1)=0`

`<=>[(x-7=0),(x-1=0):}`

`<=>[(x=7),(x=1):}`

Vậy `S={7;1}`

Answer 2

a: \(\Leftrightarrow4x^2-12x+9-4x^2+1=2\)

=>-12x=-12

=>x=1

b: \(\Rightarrow3x^2+6x-x-2-x^2+2x-1=x-3\)

\(\Leftrightarrow2x^2+7x-3=x-3\)

=>2x(x+4)=0

=>x=0 hoặc x=-4

c: =>(x-1)(x-7)=0

=>x=1 hoặc x=7