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初中数学七年级下册(573题)


用加减法解方程组\(\left\{ {\begin{array}{*{20}{l}}
{5x + y = 4(1)} \\
{7x + 2y = - 9(2)}
\end{array}} \right.\)
时,(1\( \times 2 - \)2)得\((\)  \()\)


A.\(3x = - 1\)

B.\( - 2x = 13\)

C.\(17x = - 1\)

D.\(3x = 17\)


知识点:第八章 二元一次方程组


参考答案:D

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