5a+2b=7 8a+5b=4求解
若a+b=7求解[(a^2-b^2)/(a-b)]*a+b^2+ab
a+2b/2a-3b=3 求解4b+2a/9b-6a-4a-6b/3a+6b=?
a^2+b^2=100,a/10=b/(b+10)求解a,b
3(a-b)²-7(a-b)+8(a-b)²+6(a-b),其中a-b=2.怎么写求解,
5(a+b)-3(a-b)=2 2(a+b)+5(a-b)=7
已知a*a+b*b-2a+4b+5=0,求2(a+b)(a-b)+(a-b)(a-b)-(6a*a*b-2a*b*b)/
已知a*a+b*b+a-2b+5/4=0,求【a-b】/【a+b】的值
求解 已知 sin(a+b)=1/2 ,sin(a_b)=1/3,求证:tan a=5tan b
2a/3b=--2a/-3a,-3a/b=-3a/-b,a/-5b=-a/5b,7a/-4b=7a/4b中不改变分式的值
(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b
(3a-6b/a+b)-(5a-6b/a-b)-(4a-5b/a+b)-(7a-8b/b-a)
{A+2B-3C=4,5A-6B+7C=8}求代数式A:B:C 2A-3C/A+2B