问题 解答题
填空
(1)
a+b
ab
=
(    )
a2b
;    
(2)
x2+xy
x2
=
x+y
(    )
(3)
9mn2
36n3
=
m
(   )
;    
(4)
x2+2xy+y2
x2-y2
=
x+y
(    )
答案

(1)

a+b
ab
=
a2+ab
a2b

(2)

x2+xy
x2
x(x+y)
x2
=
x+y
x

(3)

9mn2
36n3
=
9n2•m
9n2•4n
=
m
4n

(4)

x2+2xy+y2
x2-y2
=
(x+y)2
(x+y)(x-y)
=
x+y
x-y

故答案为:(1)a2+ab;(2)x;(3)4n;(4)x-y;

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