5x²-3x-5=0
所以后面求的式子中分母为0
无意义分母是5X-2X-5..哦 5x²-3x-5=0 5x²-2x-5=x 5x²-5=3x x²-1=3x/5 原式=x+5-1/x =(x²+5x-1)/x =(3x/5+5x)/x =28/5