设x1,x2是方程2x²+6x-1=0的两个跟,求下列代数式的值 (1) 1/x1+1/x2 (2)(x1+x2)² (3)(1+x1)(1+x2)
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/08 20:30:26
![设x1,x2是方程2x²+6x-1=0的两个跟,求下列代数式的值 (1) 1/x1+1/x2 (2)(x1+x2)² (3)(1+x1)(1+x2)](/uploads/image/z/3751841-65-1.jpg?t=%E8%AE%BEx1%2Cx2%E6%98%AF%E6%96%B9%E7%A8%8B2x%26%23178%3B%2B6x-1%3D0%E7%9A%84%E4%B8%A4%E4%B8%AA%E8%B7%9F%2C%E6%B1%82%E4%B8%8B%E5%88%97%E4%BB%A3%E6%95%B0%E5%BC%8F%E7%9A%84%E5%80%BC+%EF%BC%881%EF%BC%89+1%2Fx1%2B1%2Fx2++++++%EF%BC%882%EF%BC%89%EF%BC%88x1%2Bx2%EF%BC%89%26%23178%3B+++++%EF%BC%883%EF%BC%89%EF%BC%881%2Bx1%EF%BC%89%EF%BC%881%2Bx2%EF%BC%89)
xRN@ibֈƖ1.tkD7]aҐB _ !Q?љiYL@s=̽ws3ׁ˸=ͩ?d}kd]=
)CVēt-dzFMhTR+ +LI9,4
cR I$*BZΤ|N]W}m4o1hi%*h$U?+=j1'Dt1k>,2>8XwDb$ɰFoNgBhZcH(aPC-g}Y0.2Ȭ.+Tn" \cj^cd?Nk"jL(TÖy~*.uRFAt"6-b
ﶡI5Cle,G?U{
设x1,x2是方程2x²+6x-1=0的两个跟,求下列代数式的值 (1) 1/x1+1/x2 (2)(x1+x2)² (3)(1+x1)(1+x2)
设x1,x2是方程2x²+6x-1=0的两个跟,求下列代数式的值 (1) 1/x1+1/x2 (2)(x1+x2)² (3)(1+x1)(1+x2)
设x1,x2是方程2x²+6x-1=0的两个跟,求下列代数式的值 (1) 1/x1+1/x2 (2)(x1+x2)² (3)(1+x1)(1+x2)
根据题意得
x1+x2=-3
x1x2=-1/2
∴1/x1²+1/x2²=(x1²+x2²)/x1²x2²=[(x1+x2)²-2x1x2]/(x1x2)²=[3²-2×(-1/2)]/(-1/2)²=40
2 、(x1+x2)²=9
3、(1+x1)(1+x2)=1+(x1+x2)+x1x2=1+3-1/2=7/2
你的好评是我前进的动力.
我在沙漠中喝着可口可乐,唱着卡拉ok,骑着狮子赶着蚂蚁,手中拿着键盘为你答题!