神马作文网5(a*a*b-3*a*a*b)-2*(a*a*b-7*a*b*b)
a+b>a-b,
(a-b)(a b)
a/b-b/a
a-b>a,a+b
5(a+b)-3(a-b)=2 2(a+b)+5(a-b)=7
(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)
3a/a-4b +a+b/4b-a -7b/a-4b
_Max(a,b) a>b?a:b
a(a+b)-b(a-b)
因式分解（a-b)-3a+3b (a+b)(a-b)-2b(3a-5b)
[（a+2b)(a-2b)-(2a-b)²+(3a-b)(3a-5b)]÷2a