trung nguyen Toán 9

Giải phương trình sau : căn (3x^2-4x) = 2x-3

Giải phương trình sau :

\sqrt{3x^2-4x} = 2x-3

1
1 Câu trả lời
  • Bơ

    \begin{matrix}
  \sqrt {3{x^2} - 4x}  = 2x - 3 \hfill \\
  DK:3{x^2} - 4x \ne 0 \Leftrightarrow \left\{ {\begin{array}{*{20}{c}}
  {x \ne 0} \\ 
  {x \ne \frac{4}{3}} 
\end{array}} \right. \hfill \\
  \sqrt {3{x^2} - 4x}  = 2x - 3 \hfill \\
   \Leftrightarrow \left\{ {\begin{array}{*{20}{c}}
  {2x - 3 \geqslant 0} \\ 
  {3{x^2} - 4x = {{\left( {2x - 3} \right)}^2}} 
\end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}}
  {x \geqslant \frac{3}{2}} \\ 
  {3{x^2} - 4x = 4{x^2} - 12x + 9} 
\end{array}} \right. \hfill \\
   \Leftrightarrow \left\{ {\begin{array}{*{20}{c}}
  {x \geqslant \frac{3}{2}} \\ 
  { - {x^2} + 8x - 9 = 0} 
\end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}}
  {x \geqslant \frac{3}{2}} \\ 
  {\left[ {\begin{array}{*{20}{c}}
  {x = 4 + \sqrt 7 \left( {tm} \right)} \\ 
  {x = 4 - \sqrt 7 \left( L \right)} 
\end{array}} \right.} 
\end{array}} \right. \hfill \\ 
\end{matrix}

    0 Trả lời 12/08/22
    Tìm thêm: Toán 9