已知:4X-3Y-6Z=0,X+2Y-7Z=0(XYZ不等于0),求X+5Y+7Z/2X3Y+6Z的值

已知:4X-3Y-6Z=0,X+2Y-7Z=0(XYZ不等于0),求X+5Y+7Z/2X3Y+6Z的值
已知:4X-3Y-6Z=0,X+2Y-7Z=0(XYZ不等于0),求X+5Y+7Z/2X3Y+6Z的值

已知:4X-3Y-6Z=0,X+2Y-7Z=0(XYZ不等于0),求X+5Y+7Z/2X3Y+6Z的值
把z看作常数
{4x-3y=6z
{x+2y=7z
解之得
{x=3z
{y=2z
把x=3z,y=2z代入X+5Y+7Z/2X+3Y+6Z
=3z+10z+7z/6z+6z+6z
=20z/18z
=10/9