x1,x2是关于x的一元二次方程x²-bx+k=0的两个实数根,x1+x2²-x1-x2=1151)求K2)求x1²+x2²+8
来源:学生作业帮助网 编辑:作业帮 时间:2024/08/11 12:40:39
![x1,x2是关于x的一元二次方程x²-bx+k=0的两个实数根,x1+x2²-x1-x2=1151)求K2)求x1²+x2²+8](/uploads/image/z/5197203-27-3.jpg?t=x1%2Cx2%E6%98%AF%E5%85%B3%E4%BA%8Ex%E7%9A%84%E4%B8%80%E5%85%83%E4%BA%8C%E6%AC%A1%E6%96%B9%E7%A8%8Bx%26%23178%3B-bx%2Bk%3D0%E7%9A%84%E4%B8%A4%E4%B8%AA%E5%AE%9E%E6%95%B0%E6%A0%B9%2Cx1%2Bx2%26%23178%3B-x1-x2%3D1151%29%E6%B1%82K2%EF%BC%89%E6%B1%82x1%26%23178%3B%2Bx2%26%23178%3B%2B8)
x)0ԩ0z6cOvU
q!v6m!sx:
i kӄJA4BEJulIIg&'V&ԇivvwھӁB4"t4@F 1/ > l
x1,x2是关于x的一元二次方程x²-bx+k=0的两个实数根,x1+x2²-x1-x2=1151)求K2)求x1²+x2²+8
x1,x2是关于x的一元二次方程x²-bx+k=0的两个实数根,x1+x2²-x1-x2=115
1)求K
2)求x1²+x2²+8
x1,x2是关于x的一元二次方程x²-bx+k=0的两个实数根,x1+x2²-x1-x2=1151)求K2)求x1²+x2²+8
1、x1+x2=b
x1×x2=k
x1²+x2²-x1-x2
=(x1+x2)²-2x1×x2-(x1+x2)
∴b²-2k-b=115
k=(b²-b-115)/2
2、x1²+x2²+8
=(x1+x2)²-2x1×x2+8
=b²-2k+8
=b²-(b²-b-115)+8
=b+115+8
=b+123