题目内容
若
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A.

B.

C.

D.
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【答案】分析:本题可将x,y的值代入方程组,得到:
,再运用加减消元法或把选项代入,得出m,n的值.
解答:解:把x、y的值代入方程组,得
,
将①×2+②,得
5m=10,
m=2.
将m=2代入①,得
n=3.
故选B.
点评:本题考查的是二元一次方程组的解法,解此类题目时可将选项中的数代入,也可对方程运用加减消元法得出x、y的值.

解答:解:把x、y的值代入方程组,得

将①×2+②,得
5m=10,
m=2.
将m=2代入①,得
n=3.
故选B.
点评:本题考查的是二元一次方程组的解法,解此类题目时可将选项中的数代入,也可对方程运用加减消元法得出x、y的值.

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