a-3(-b+c-d)化简

a-3(-b+c-d)化简 a,b,c,d>0 证(a/(b+2c+3d))+(b/(c+2d+3a))+(c/d+2a+3b))+(d/(a+2b [a,b)×[c,d a,b ,c ,d 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-d)=(a-c)-(-b+d) (a/(b+2c+3d))+(b/(c+2d+3a))+(c/d+2a+3b))+(d/(a+2b+3c))>=2/3 设a,b,c满足ab+bc+cd+da=1,求证：a^3/(b+c+d)+b^3/(a+c+d)+c^3/(a+b+d) (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) 若a-b=-3,c+d=2,求(b+c)-(a-d)的值