摘要:抛物线y=ax2与直线y=kx+b(k≠0)交于A.B两点.且此两点的横坐标分别为x1,x2,直线与x轴交点的横坐标是x3,则恒有( ) A.x3=x1+x2 B.x1x2=x1x3+x2x3 C.x1+x2+x3=0 D.x1x2+x2x3+x3x1=0 解析:解方程组,得ax2-kx-b=0,可知x1+x2=,x1x2=-,x3=-, 代入验证即可.答案:B
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抛物线y=ax2与直线y=kx+b(k≠0)交于A、B两点,且此两点的横坐标分别为x1,x2,直线与x轴交点的横坐标是x3,则恒有( )
A. x3=x1+x2 B.x1x2=x1x3+x2x3
C. x1+x2+x3=0 D. x1x2+x2x3+x3x1=0
查看习题详情和答案>> 抛物线y=ax2与直线y=kx+b(k≠0)交于A、B两点,且此两点的横坐标分别为x1,x2,直线与x轴交点的横坐标是x3,则恒有( )
| A.x3=x1+x2 | B.x1x2=x1x3+x2x3 |
| C.x1+x2+x3="0" | D.x1x2+x2x3+x3x1=0 |
抛物线y=ax2与直线y=kx+b(k≠0)交于A,B两点,且此两点的横坐标分别为x1,x2,直线与x轴的交点的横坐标是x3,则恒有( )
| A、x3=x1+x2 | B、x1x2=x1x3+x2x3 | C、x3+x1+x2=0 | D、x1x2+x1x3+x2x3=0 |