数学题;3x^2+4x-5=0 则1/x1+1/x2=( ）x1^2+x2^2=( )
问题描述：
数学题;3x^2+4x-5=0 则1/x1+1/x2=( ）x1^2+x2^2=( )
答
x1+x2=-b/a=-4/3 x1*x2=c/a=-5/3
1/x1+1/x2=(x1+x2)/x1*x2=4/5
x1^2+x2^2=(x1+x2)^2-2x1*x2=16/9+10/3=46/9
答
X1+X2=-4/3 X1*X2=-5/3
1/X1+1/X2=(X1+X2)/(X1X2)=-4/3÷(-5/3)=4/5
X1²+X2²=(X1+X2)²-2X1X2=(-4/3)²-2*(-5/3)=16/9+10/3=46/9
答
3x^2+4x-5=0
x1+x2=-4/3,x1x2=-5/3
1/x1+1/x2=(x1+x2)/x1x2=4/5
x1^2+x2^2=(x1+x2)^2-2x1x2=16/9+10/3=46/9
答
4/5; 26/9