Question

已知4X-3Y-6Z=0,X+2Y-7X=0（XYZ≠0）,则X方+5Y方+7Z方分之2X方+3Y方+6Z方等于?

Answer 1

4x-3y-6z=0 ,x+2y-7z=0

解得 x=3z,y=2z

2x^2+3y^2+6z^2=2*9z^2+3*4z^2+6z^2=36z ^2

x^2+5y^2+7z^2=9z^2+5*4z^2+7z^2=36z^2

（2x^2+3y^2+6z^2）/(x^2+5y^2+7z^2)

=1