通分这三个分式. x/x^2-4 ,1/4-2x, 2/x^2-4x+4
问题描述:
通分这三个分式. x/x^2-4 ,1/4-2x, 2/x^2-4x+4
答
x/(x²-4)=2x(x-2)/2(x-2)²(x+2);
1/(4-2x)=-(x-2)(x+2)/2(x-2)²(x+2);
2/(x-2)²=4(x+2)/(2(x-2)²(x+2).