Tìm x A)5x(x-2000)-x+2000=0 B)(12x-5)(4x-1)+(3x-7)(1-16x)=81 C)3x²-3x=0 D)4x(x-7)-4x²=56

Bạn tham khảo:

a. $5x(x-2000)-(x-2000)=0$
⇔$(5x-1)(x-2000)=0$

⇔\(\left[ \begin{array}{l}x=\dfrac{1}{5}\\x=2000\end{array} \right.\) 

b.$(12x-5)(4x-1)+(3x-7)(1-16x)=81$

⇔$48x^{2}-32x+5-48x^2+115x-83=0$

⇔$83x=83$

⇔$x=1$

c.  $3x^{2}-3x=0$

⇔$3x(x-1)=0$

⇔\(\left[ \begin{array}{l}x=0\\x=1\end{array} \right.\)

d. $4x(x-7)-$$4x^{2}=56$

⇔$4x^{2}-28x-4x^2=56$

⇔$-28x=56$

⇔$x=-2$

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