Question

計(jì)算：

1

6x-4y

-

1

6x+4y

-

3x

4y2-9x2

．

Answer 1

分析：根據(jù)異分母分式相加減，先通分，再加減，可得答案．

解答：解：原式=

1

2(3x-2y)

-

1

2(3x+2y)

+

3x

(3x+2y)(3x-2y)

=

(3x+2y)-(3x-2y)+6x

2(3x+2y)(3x-2y)

=

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

2(3x+2y)(3x-2y)

=

2(3x+2y)

2(3x+2y)(3x-2y)

=

1

3x-2y

．

點(diǎn)評：本題考查了分式的加減，先通分花成同分母分時，再加減．