x/x^2-25-5/x^2+10x+25

问题描述:

x/x^2-25-5/x^2+10x+25

原式=x/(x+5)(x-5)-5/(x+5)²
=[x(x+5)-5(x-5)]/(x+5)²(x-5)
=(x²+25)/[(x+5)²(x-5)]