如图抛物线与x轴相交于B,C两点,与y轴交于点A,P(2a,-4a²+7a+2)(a是实数)在抛物线上,直线y=kx+b经过A,B两点
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![如图抛物线与x轴相交于B,C两点,与y轴交于点A,P(2a,-4a²+7a+2)(a是实数)在抛物线上,直线y=kx+b经过A,B两点](/uploads/image/z/6973003-19-3.jpg?t=%E5%A6%82%E5%9B%BE%E6%8A%9B%E7%89%A9%E7%BA%BF%E4%B8%8Ex%E8%BD%B4%E7%9B%B8%E4%BA%A4%E4%BA%8EB%2CC%E4%B8%A4%E7%82%B9%2C%E4%B8%8Ey%E8%BD%B4%E4%BA%A4%E4%BA%8E%E7%82%B9A%2CP%282a%2C-4a%26%23178%3B%2B7a%2B2%29%28a%E6%98%AF%E5%AE%9E%E6%95%B0%29%E5%9C%A8%E6%8A%9B%E7%89%A9%E7%BA%BF%E4%B8%8A%2C%E7%9B%B4%E7%BA%BFy%3Dkx%2Bb%E7%BB%8F%E8%BF%87A%2CB%E4%B8%A4%E7%82%B9)
如图抛物线与x轴相交于B,C两点,与y轴交于点A,P(2a,-4a²+7a+2)(a是实数)在抛物线上,直线y=kx+b经过A,B两点
如图抛物线与x轴相交于B,C两点,与y轴交于点A,P(2a,-4a²+7a+2)(a是实数)在抛物线上,直线y=kx+b经过A,B两点
如图抛物线与x轴相交于B,C两点,与y轴交于点A,P(2a,-4a²+7a+2)(a是实数)在抛物线上,直线y=kx+b经过A,B两点
∵P(2a,-4a²+7a+2)在抛物线上,
∴X=2a,
Y=-(2a)^2+7/2(2a)+2=-X^2+7/2X+2,
令X=0,Y=2,∴A(0,2),
令Y=0,-X^2+7/2X+2=0,
X=-1/2或4,
∴B(-1/2,0)或(4,0),
∴直线AB:Y=4X+2或Y=-1/2X+2.