Question

5x(x-2)-2=0

Answer 1

sai đề ko bn?

Answer 2

đề có sai ko bn?

Answer 3

`5x(x-2)-2=0`

`<=> 5x^2 -10x -2 =0`

`=> Delta = (-10)^2 -4*5*(-2) = 140 `

`=> Delta >0`

`=>PT ` có 2 nghiệm

\(x=\dfrac{-\left(-10\right)\pm\sqrt{\Delta}}{2\cdot5}=\dfrac{10\pm\sqrt{140}}{10}=\dfrac{10\pm2\sqrt{35}}{10}\)

\(x=\dfrac{5+\sqrt{35}}{5}\)

Vậy \(S=\left\{\dfrac{5\pm\sqrt{35}}{5}\right\}\)

Answer 4

`5x(x-2) -2 =0`

`<=> 5x^2 -10 -2 =0`

`<=> 5x^2 = 2+10 =12`

`<=> x^2 =12/5`

`<=> x = +- sqrt{12/5}`