A+B+C+D=60,5A=B-1=C+4=D/2,A.B.C.
( )-(c-d)=(a-c)-(-b+d)
a b c d* d_________=d c b a
A B C D × 9 ___________________ D C B A (1) A = ( )(2) B = (
a+b+c+d=2a;a+b+c+d=4b;a+b+c+d=6c;a+b+c+d=8d 求a,b,c,d
已知a:b=c:d,求证(a+c):(a-c)=(b+d):(b-d)
a>b>c>d>0.a/b=c/d怎么证明a+d>c+b
实数a,b,c,d满足d>c;a+b=c+d;a+d
4元1次方程求速解1:A+B+C=134B+C+D=131A-B-C=D=1A+B+C+D=?2:2A+B-5C+D=8
已知a/b=c/d,求证a+2b/b=c+2d/d
D = b+c c+d a+b
求证(b,c,d)a+(c,a,d)b+(a,b,d)c+(b,a,c)d=0 a,b,c,d皆为向量>
已知abcd为实数,M=4(a-b)(c-d)N=(a-b)(c-b) (d-a)(c-b) (c-d)(c-b) (a