(a-2b+c+3d)(a+2b-c+3d)=
已知:a/b=c/d,求证:(2a+3b)/(a+b)=(2c+3d)/(c+d)
已知a/b=c/d,求证2a+3b/a+b=2c+3d/c+d
a,b,c,d>0 证(a/(b+2c+3d))+(b/(c+2d+3a))+(c/d+2a+3b))+(d/(a+2b
(a/(b+2c+3d))+(b/(c+2d+3a))+(c/d+2a+3b))+(d/(a+2b+3c))>=2/3
若a-b=-3,c+d=2,求(b+c)-(a-d)的值
已知a-b=3,c +d=2,(b+c )-(a-d)的值为?
已知a-b=-5,b-c=3,求(b-2d+c)-(a-2d+b)
已知a/b=c/d,求证a+2b/b=c+2d/d
已知a-b=2,b-c=-3,c-d=5,则【a-c】【b-d】【c-d】的值
3a-2b+c=0 12a+4b+c=0 -a+b-c+d=0 8a+4d+2c+d=0求a.b.c.d的值,
(a+b+2c-3d)(a+b-2c+3d)用乘法公式计算.
计算(3a+b-2c+d)(3a-b+2c+d)