Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: giải pt ( 3x – 1 )^2 = x ( – 3x + 1)

Toán Lớp 8: giải pt ( 3x – 1 )^2 = x ( – 3x + 1)

Comments ( 2 )

  1. (3x-1)^2=x(-3x+1)
    ⇔9x^2-6x+1=-3x^2+x
    ⇔12x^2-7x+1=0
    ⇔12x^2-3x-4x+1=0
    ⇔3x(4x-1)-(4x-1)=0
    ⇔(3x-1)(4x-1)=0
    ⇔\(\left[ \begin{array}{l}3x-1=0\\4x-1=0\end{array} \right.\) 
    ⇔\(\left[ \begin{array}{l}x=1/3\\x=1/4\end{array} \right.\) 

  2. $(3x-1)^{2}$ = x ( – 3x + 1)
    ⇒ $(3x-1)^{2}$ = -x (3x – 1)
    ⇒ $(3x-1)^{2}$ + x (3x – 1) = 0
    ⇒ (3x – 1) (3x – 1 + x) = 0
    ⇒ (3x – 1) (4x – 1) = 0
    ⇒ \(\left[ \begin{array}{l}3x-1=0\\4x – 1=0\end{array} \right.\) 
    ⇒ \(\left[ \begin{array}{l}3x=1\\4x =1\end{array} \right.\) 
    ⇒ \(\left[ \begin{array}{l}x= \dfrac{1}{3} \\x = \dfrac{1}{4} \end{array} \right.\) 
                                Vậy x ∈ {$\dfrac{1}{3}$ , $\dfrac{1}{4}$ }

Leave a reply

222-9+11+12:2*14+14 = ? ( )

About Khánh Ly