已知4x-3y-6z=0,x+2y-7z=0,x²+5y²+7z²分之2x²+3y²+6z²=?

已知4x-3y-6z=0,x+2y-7z=0,x²+5y²+7z²分之2x²+3y²+6z²=?
已知4x-3y-6z=0,x+2y-7z=0,x²+5y²+7z²分之2x²+3y²+6z²=?

已知4x-3y-6z=0,x+2y-7z=0,x²+5y²+7z²分之2x²+3y²+6z²=?
由4x-3y-6z=0及x+2y-7z=0得
x=3z,y=2z,(z≠0)
代入代数式,
(5x²+2y²-z²)/(2x²-3y²-10z²)
=(45z²+8 z²-z²)/(18 z²-12 z²-10 z²)
=52÷(-4)
= -13.

(3)£¨2x 2;+3y 2;+6z 2;£©\\(x 2;+5y 2;+7z 2;£© 4x-3y-6z=0 x+2y-7z=0 (1)ÏûÈ¥zÏ7(4x-3y-6z) - 6(x+2y-7z) = 0