thank you已知x+3y+5z=0,2x+3y+z=0 且x、y、z.都不是0,则（2y-z）（2y+z）除以z的平方等多少?

thank you已知x+3y+5z=0,2x+3y+z=0 且x、y、z.都不是0,则（2y-z）（2y+z）除以z的平方等多少? 已知,x/2=y/3=z/4,则(2x+y-z)/(3x-2y+z)=?Thank you for your help!嘻嘻…… 已知非零的实数x,y,z满足2^x=5^y=10^z,求证1/x+1/y=1/z?Thank you! 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 已知z、y、z同时满足x+3y-5z=0,2x-y-3z=0,求x:y:z 已知{x-5y+2z=0 3x-5y-4z=0,求x：y:z 已知x+4y-3z=0,4x-5y+2z=0,则x：y：z 已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z 已知x+y+z=0求证x*x*x+y*y*y+z*z*z=3xyz 已知方程组3x+5y+3z=0,3x-5y-8z=0,并且z≠0,求x:z和y:z 已知x+y-z=0,2x-y+2z=0 求（3x-2y+5z)/(5x-3y+2z)的值 已知x-y+z=0,3x+y-5z=0,则x+y+z/x+2y-3z=? 已知:x+y+z=0,5x-3y-z=0,求:5x-y+z/2x+8y+7z 的值 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. 已知3x+4y+5z=0,2x+3y-4z=0,求(x+y+z)/(x-y+z) 已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/（除以）x-y+z的值. 已知x+2y-3z=0,2x+3y+5z=0,求(x+y+z)除以（x-y+z) 已知{3x+4y+5z=0,2x+3y-4z=0,求x+y+z/x-y+z的值.