方程组2x-y=8p 4x+7y=7p的解是方程x+y=5的解,求p的值
人气：223 ℃ 时间：2019-08-17 22:06:42
解答
2x-y=8p①
4x+7y=7p ②
①+②就得
6x+6y=15p
即6（x+y)=15p ③
还有x+y=5
于是把
x+y=5代进去③就得
6×5=15p
从而解得
p=2
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