2X^2-3X-7=0
X1+X2=3/2,X1X2=-7/2
1/X1+1/X2=(X1+X2)/(X1X2)=-3/7
(1/X1)*(1/X2)=1/(X1X2)=-2/7
所以所求方程是
x^2+3x/7-2/7=0
即7x^2+3x-2=0
2X^2-3X-7=0
X1+X2=3/2,X1X2=-7/2
1/X1+1/X2=(X1+X2)/(X1X2)=-3/7
(1/X1)*(1/X2)=1/(X1X2)=-2/7
所以所求方程是
x^2+3x/7-2/7=0
即7x^2+3x-2=0