如果x1x2是一元二次方程ax2+bx+c=0的两根如果x1x2是一元二次方程ax2+bx+c=0的两根 那么有x1+x2=-b/a,x1*x2=c/a已知X1,X2是方程X²+6x+3=0的两个实数根,不解方程,求下列各式的值(1) X1²+X2²(2)1/X1+1/X2
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![如果x1x2是一元二次方程ax2+bx+c=0的两根如果x1x2是一元二次方程ax2+bx+c=0的两根 那么有x1+x2=-b/a,x1*x2=c/a已知X1,X2是方程X²+6x+3=0的两个实数根,不解方程,求下列各式的值(1) X1²+X2²(2)1/X1+1/X2](/uploads/image/z/1598931-27-1.jpg?t=%E5%A6%82%E6%9E%9Cx1x2%E6%98%AF%E4%B8%80%E5%85%83%E4%BA%8C%E6%AC%A1%E6%96%B9%E7%A8%8Bax2%2Bbx%2Bc%3D0%E7%9A%84%E4%B8%A4%E6%A0%B9%E5%A6%82%E6%9E%9Cx1x2%E6%98%AF%E4%B8%80%E5%85%83%E4%BA%8C%E6%AC%A1%E6%96%B9%E7%A8%8Bax2%2Bbx%2Bc%3D0%E7%9A%84%E4%B8%A4%E6%A0%B9+%E9%82%A3%E4%B9%88%E6%9C%89x1%2Bx2%3D-b%2Fa%2Cx1%2Ax2%3Dc%2Fa%E5%B7%B2%E7%9F%A5X1%2CX2%E6%98%AF%E6%96%B9%E7%A8%8BX%26sup2%3B%2B6x%2B3%3D0%E7%9A%84%E4%B8%A4%E4%B8%AA%E5%AE%9E%E6%95%B0%E6%A0%B9%2C%E4%B8%8D%E8%A7%A3%E6%96%B9%E7%A8%8B%2C%E6%B1%82%E4%B8%8B%E5%88%97%E5%90%84%E5%BC%8F%E7%9A%84%E5%80%BC%281%29+X1%26sup2%3B%2BX2%26sup2%3B%282%291%2FX1%2B1%2FX2)
如果x1x2是一元二次方程ax2+bx+c=0的两根如果x1x2是一元二次方程ax2+bx+c=0的两根 那么有x1+x2=-b/a,x1*x2=c/a已知X1,X2是方程X²+6x+3=0的两个实数根,不解方程,求下列各式的值(1) X1²+X2²(2)1/X1+1/X2
如果x1x2是一元二次方程ax2+bx+c=0的两根
如果x1x2是一元二次方程ax2+bx+c=0的两根 那么有x1+x2=-b/a,x1*x2=c/a
已知X1,X2是方程X²+6x+3=0的两个实数根,不解方程,求下列各式的值
(1) X1²+X2²
(2)1/X1+1/X2
(3)X2/X1+X1/X2
如果x1x2是一元二次方程ax2+bx+c=0的两根如果x1x2是一元二次方程ax2+bx+c=0的两根 那么有x1+x2=-b/a,x1*x2=c/a已知X1,X2是方程X²+6x+3=0的两个实数根,不解方程,求下列各式的值(1) X1²+X2²(2)1/X1+1/X2
x1+x2=-b/a=-6 x1*x2=c/a=3
(1)
X1²+X2²
=(x1+x2)²-2(x1*x2)
=(-b/a)²-(2c/a)
=36-6
=30
(2)
1/X1+1/X2
=X2/(X1*X2)+X1/(X1*X2)
=X1+X2/X1*X2
=-6/3
=-2
(3)
X2/X1+X1/X2
=X2²/(X1*X2)+ X1²(/X1*X2)
=X1²+X2²/(X1*X2)
=30/3
=10
好歹也是我辛辛苦苦做的,辛辛苦苦打的
如果我做错了,请告诉我一声,
X1+X2=-6, X1*X2=3
(1)X1²+X2²=(X1+X2)²-2X1X2=36-6=30
(2)1/X1+1/X2=(X1+X2)/(X1*X2)=-6/3=-2
(3)X2/X1+X1/X2 =(X1²+X2²)/(X1*X2)=30/3=10
已知x1,x2是方程x²+6x+3=0的两个实数根,不解方程,求下列各式的值
x1+x2=-6
x1x2=3
(1) x1²+x2²=(x1+x2)²-2x1x2=30
(2)1/x1+1/x2=(x1+x2)/(x1x2)=-2
(3)x2/x1+x1/x2=(x1²+x2²)/(x1x2)=10
x1+x2=-6,x1x2=3
(1) X1²+X2²
=(x1+x2)^-2x1x2
=36-2*3=30
(2)1/X1+1/X2
=(x1+x2)/x1x2=-6/3=-2
(3)X2/X1+X1/X2
= (X1²+X2²)/x1x2=30/3=10