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 6: (3^x-81)*(6x-12)=0 hỏi x bằng bao nhiêu ?

Toán Lớp 6: (3^x-81)*(6x-12)=0
hỏi x bằng bao nhiêu ?

Comments ( 2 )

  1. (3^x – 81).(6x – 12) = 0
    => 3^x – 81 = 0 hoặc 6x – 12 = 0
    Th1:
    3^x – 81 = 0
    3^x = 0 + 81
    3^x = 81
    3^x = 3^4
    => x = 4
    Th2:
    6x – 12 = 0
    6x = 0 +12
    6x = 12
    x = 12 : 6
    x = 2
    Vậy x in {4; 2}

  2. (3^x-81).(6x-12)=0
    ⇒(3^x-81).6.(x-2)=0
    $⇒\left[\begin{matrix} 3^x-81=0\\ x-2=0\end{matrix}\right.$
    $⇒\left[\begin{matrix} 3^x=81\\ x=2\end{matrix}\right.$
    $⇒\left[\begin{matrix} 3^x=3^4\\ x=2\end{matrix}\right.$
    $⇒\left[\begin{matrix} x=4\\ x=2\end{matrix}\right.$

Leave a reply

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