3(12+23+34+.+99+100)=?A:97x98x99 B:98x99x100 C:99x100x101 D:
1/1x2x3+1/2x3x4+1/3x4x5+.1/98x99x100=
( )-(c-d)=(a-c)-(-b+d)
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,
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
C语言 d = a > 12 b :
已知:(10a+b)(10c+d)=(10a+c)(10b+d)=1000a+100b+10c+d,求a.b.c.d.
已知:(10a+b)(10c+d)=(10a+c)(10b+d)=1000a+100b+10c+d,求a.b.c.d.(
(a/(b+2c+3d))+(b/(c+2d+3a))+(c/d+2a+3b))+(d/(a+2b+3c))>=2/3
a b c d* d_________=d c b a
解方程组:3a+b+c+d=0 a+3b+c+d=12 a+b+3c+d=12 a+b+c+3d=8
实数a,b,c,d满足d>c;a+b=c+d;a+d