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 9: Giải phương trình: `\sqrt{x+1}=x-1`

Toán Lớp 9: Giải phương trình:
\sqrt{x+1}=x-1

Comments ( 2 )

  1. ĐKXĐ: x-1 ge 0 <=>xge1
    ____________________________
    sqrt{x+1}=x-1 (xge1)
    <=>(sqrt{x+1})^2=(x-1)^2
    <=>x+1=x^2-2x+1
    <=>x^2-3x=0
    <=>x(x-3)-0
    <=> \(\left[ \begin{array}{l}x=0(Loại)\\x=3(Tm)\end{array} \right.\)
    Vậy S={3}
     

  2. $\sqrt{x+1}=x-1$ ĐK: $x\geq1$
    ⇔ $(\sqrt{x+1})^2=(x-1)^2$
    ⇔ $x+1=x^2-2x+1$
    ⇔ $x^2-2x+1-x-1=0$
    ⇔ $x^2-3x=0$
    ⇔ $x(x-3)=0$
    ⇔ $\left[\begin{matrix} x=0(loại)\\ x=3\end{matrix}\right.$

Leave a reply

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

About Chi