分式加减题.(1\X-3)-(1\X^2-9)-(X-1\6-2X)=?(5\X^-2X)-(4\X^2+2X)-(3\X^2-4)=?过后追分~555
问题描述:
分式加减题.
(1\X-3)-(1\X^2-9)-(X-1\6-2X)=?
(5\X^-2X)-(4\X^2+2X)-(3\X^2-4)=?
过后追分~
555
答
1/(x-3)-1/(x^2-9)-(x-1)/(6-2x)=1/(x-3)-1/((x+3)(x-3))-(x-1)/(2(3-x))=1/(x-3)-1/((x+3)(x-3))+(x-1)/(2(x-3))分子,分母各乘以2(x-3)(x+3)=2(x+3)-2+(x-1)(x+3)=2x+6-2+x^2+2x-3=x^2+4x+3=(x+1)(x+3)第二题看不懂...