解方程1/x2+x+1/x2+3x+2+1/x2+5x+6+1/x2+7x+12=4/21得_.
问题描述:
解方程
+1
x2+x
+1
x2+3x+2
+1
x2+5x+6
=1
x2+7x+12
得______. 4 21
答
方程两边同乘x(x+1)(x+2)(x+3)(x+4),得(x+2)(x+3)(x+4)+x(x+3)(x+4)+x(x+1)(x+4)+x(x+1)(x+2)=421x(x+1)(x+2)(x+3)(x+4),∴(x+3)(x+4)(2x+2)+x(x+1)(2x+6)=421x(x+1...