Question

計算化簡：

6y

x2-y2

-

2

y-x

+

3

x+y

=______．

Answer 1

原式=

6y

(x+y)(x-y)

+

2

x-y

+

3

x+y

=

6y

(x+y)(x-y)

+

2(x+y)

(x+y)(x-y)

+

3(x-y)

(x+y)(x-y)

=

6y+2x+2y+3x-3y

(x+y)(x-y)

=

6y

(x+y)(x-y)

+

2(x+y)

(x+y)(x-y)

+

3(x-y)

(x+y)(x-y)

=

5(x+y)

(x+y)(x-y)

=

5

x-y

．
故答案為

5

x-y

．