Mc Trà My Hải Dương 5 tuổi Nguyễn Trà My Hỏi đáp Toán 9 Toán 9 Bài tập Toán 9

Giải hệ phương trình không chứa tham số

4 7

Xóa Đăng nhập để viết

7 Câu trả lời

Captain
$\begin{matrix} \left\{ {\begin{array}{*{20}{c}} {y = 2x - 1} \\ {x + 3y = 11} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {2x - y = 1} \\ {x + 3y = 11} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {2x - y = 1} \\ {2x + 6y = 22} \end{array}} \right. \hfill \\ \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {2x - y = 1} \\ {7y = 21} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 2} \\ {y = 3} \end{array}} \right. \hfill \\ \end{matrix}$
Trả lời hay
1 Trả lời 23/08/22
Đen2017
$\begin{matrix} \left\{ {\begin{array}{*{20}{c}} {x + 3y - 2 = 0} \\ {\dfrac{x}{2} = \dfrac{y}{3} + 1} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 2 - 3y} \\ {\dfrac{x}{2} = \dfrac{y}{3} + 1} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 2 - 3y} \\ {\dfrac{{2 - 3y}}{2} = \dfrac{y}{3} + 1} \end{array}} \right. \hfill \\ \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 2 - 3y} \\ {3\left( {2 - 3y} \right) = 2y + 6} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 2 - 3y} \\ {6 - 9y = 2y + 6} \end{array}} \right. \hfill \\ \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 2 - 3y} \\ {11y = 0} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 2} \\ {y = 0} \end{array}} \right. \hfill \\ \end{matrix}$
0 Trả lời 23/08/22
Captain
$\begin{matrix} \left\{ {\begin{array}{*{20}{c}} {x\left( {x + 2} \right) - \left( {x - 2} \right)x + y = 3} \\ {y\left( {2 + y} \right) = y\left( {y - 4} \right) + 3x} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {{x^2} + 2x - {x^2} + 2x + y = 3} \\ {2y + {y^2} = {y^2} - 4y + 3x} \end{array}} \right. \hfill \\ \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {4x + y = 3} \\ {6y = 3x} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {4x + y = 3} \\ {2y = x} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {4.\left( {2y} \right) + y = 3} \\ {2y = x} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {y = \dfrac{1}{3}} \\ {x = \dfrac{2}{3}} \end{array}} \right. \hfill \\ \end{matrix}$
0 Trả lời 23/08/22
Đen2017
$\begin{matrix} \left\{ {\begin{array}{*{20}{c}} {x = 3 - 2y} \\ {y = - 1 + 2x} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 3 - 2y} \\ {y = - 1 + 2.\left( {3 - 2y} \right)} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 3 - 2y} \\ {y = - 1 + 6 - 4y} \end{array}} \right. \hfill \\ \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 3 - 2y} \\ {5y = 5} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 1} \\ {y = 1} \end{array}} \right. \hfill \\ \end{matrix}$
0 Trả lời 23/08/22
Đội Trưởng Mỹ
$\begin{matrix} \left\{ {\begin{array}{*{20}{c}} {3x = 17 - y} \\ {x - 2y = 1} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {3x = 17 - y} \\ {x = 1 + 2y} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {3\left( {1 + 2y} \right) = 17 - y} \\ {x = 1 + 2y} \end{array}} \right. \hfill \\ \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {3 + 6y = 17 - y} \\ {x = 1 + 2y} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {7y = 14} \\ {x = 1 + 2y} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {y = 2} \\ {x = 5} \end{array}} \right. \hfill \\ \end{matrix}$
0 Trả lời 23/08/22
Su kem
$\begin{matrix} \left\{ {\begin{array}{*{20}{c}} {y = 3 - 2x} \\ {\frac{x}{4} = \frac{y}{3} - 1} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {y = 3 - 2x} \\ {\frac{x}{4} = \frac{{3 - 2x}}{3} - 1} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {y = 3 - 2x} \\ {3x = 4\left( {3 - 2x} \right) - 12} \end{array}} \right. \hfill \\ \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {y = 3 - 2x} \\ {3x = 12 - 8x - 12} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {y = 3 - 2x} \\ {11x = 0} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {y = 1} \\ {x = 0} \end{array}} \right. \hfill \\ \end{matrix}$
0 Trả lời 23/08/22
Bơ
$\left\{ {\begin{array}{*{20}{c}} {3x + y = 5} \\ {3 - x = y} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {3x + y = 5} \\ {x + y = 3} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {2x = 2} \\ {x + y = 3} \end{array}} \right. \Leftrightarrow \left\{ {\begin{array}{*{20}{c}} {x = 1} \\ {y = 2} \end{array}} \right.$
0 Trả lời 23/08/22