A;___________city!B;yes,lots of tourists come to visit this city every year.A.how lively B.what a beautiful 应该选a\b

A;___________city!B;yes,lots of tourists come to visit this city every year.A.how lively B.what a beautiful 应该选a (a+b).(a-b) a/b-b/a a+b>a-b, a-b>a,a+b 计算a+b/b-a-b/b -2a(a+b)+b(a+b) 化简|a|+|-b|-|a-b|-|a+b| 化简 |b|-|a|+|a-b|+|a+b| [(a+b)(a-b)-(a-b) (a+b)(a-b)-a-b因式分解 化简 |a-b|+|a+b|-|a-b| 因式分解 a(a+b)-b(a-b) a(a+b)-b(a-b) A*b/a>A ,那么a/b a+b |a+b| a>,b