1/x-4-2x/x²-4² 等于多少?
问题描述:
1/x-4-2x/x²-4² 等于多少?
答
=(x+4)/(x+4)(x-4) -2x/(x+4)(x-4)
=(x+4-2x)/(x+4)(x-4)
=-(x-4)/(x+4)(x-4)
=-1/(x+4)