以知方程组{⑴4x-2y-6z=0⑵x-5y-7z=0.求7x+2y+6z/3x+5y+7z的值.
1个回答
将z当常数:
4x-2y=6z
x-5y=7z 解二元二次方程得X=8/9Z,Y=-11/9Z
代入原式,可将Z约掉,
原式=-8
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