1) Giải phương trình: \({x^2} + 8x + 7 = 0\)
2) Giải hệ phương trình: \(\left\{ \begin{array}{l}2x - y = - 6\\5x + y = 20\end{array} \right.\)
A.\(\begin{array}{l}1)\,\,S = \left\{ { - 1;\, - 7} \right\}\\2)\,\left( {x;\,y} \right) = \left( {2;\,10} \right)\end{array}\)
B.\(\begin{array}{l}1)\,\,S = \left\{ {1;\,7} \right\}\\2)\,\left( {x;\,y} \right) = \left( {2;\,10} \right)\end{array}\)
C.\(\begin{array}{l}1)\,\,S = \left\{ { - 1;\, - 7} \right\}\\2)\,\left( {x;\,y} \right) = \left( { - 2;\, - 10} \right)\end{array}\)
D.\(\begin{array}{l}1)\,\,S = \left\{ {1;\,7} \right\}\\2)\,\left( {x;\,y} \right) = \left( { - 2; - \,10} \right)\end{array}\)
2) Giải hệ phương trình: \(\left\{ \begin{array}{l}2x - y = - 6\\5x + y = 20\end{array} \right.\)
A.\(\begin{array}{l}1)\,\,S = \left\{ { - 1;\, - 7} \right\}\\2)\,\left( {x;\,y} \right) = \left( {2;\,10} \right)\end{array}\)
B.\(\begin{array}{l}1)\,\,S = \left\{ {1;\,7} \right\}\\2)\,\left( {x;\,y} \right) = \left( {2;\,10} \right)\end{array}\)
C.\(\begin{array}{l}1)\,\,S = \left\{ { - 1;\, - 7} \right\}\\2)\,\left( {x;\,y} \right) = \left( { - 2;\, - 10} \right)\end{array}\)
D.\(\begin{array}{l}1)\,\,S = \left\{ {1;\,7} \right\}\\2)\,\left( {x;\,y} \right) = \left( { - 2; - \,10} \right)\end{array}\)
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Hóa Học lớp 12
