已知4x-3y-6z=0 ① ,x+2y-7z=0 ②,且x,y,z均不为0,求3x+2y+z÷x+2y+3z的值
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已知4x-3y-6z=0 ① ,x+2y-7z=0 ②,且x,y,z均不为0,求3x+2y+z÷x+2y+3z的值
把xyz三个未知数中的一个看成已知数解方程组,再把结果代入式子计算;手机写步骤慢希望能理解
再问: 4x-3y-6z=0 (1) x+2y-7z=0 (2) ��(2)��x=7z-2y (3) ��(3)����(1)�� 28z-8y-3y-6z=0 y=2z ��y=2z����(3)�� x=7z-4z=3z ��x=3z��y=2z���� 3x+2y+z/x+2y+3z�� (3x+2y+z)/(x+2y+3z) =(9z+4y+z)/(3z+4z+3z) =14/10 =7/5�ɣ�������
再答: 对
再问: 4x-3y-6z=0 (1) x+2y-7z=0 (2) ��(2)��x=7z-2y (3) ��(3)����(1)�� 28z-8y-3y-6z=0 y=2z ��y=2z����(3)�� x=7z-4z=3z ��x=3z��y=2z���� 3x+2y+z/x+2y+3z�� (3x+2y+z)/(x+2y+3z) =(9z+4y+z)/(3z+4z+3z) =14/10 =7/5�ɣ�������
再答: 对
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