如图已知一交函数y=-2x+6的图像与x轴交于点A，与y轴交于点C，二次函数y=ax²+bx+c（a≠0）的图像过A,C

(1) A(3, 0), C(0, 6) 代入y=ax²+bx+c c = 6 b = -3a -2 y = ax² -(3a+2)x + 6 设B(p, 0), 3(A的横坐标), p为ax² -(3a+2)x + 6 = 0的解 y = ax² -(3a+2)x + 6 = a(x-p)(x-3) = ax² -(p+3)ax + 3ap 3a+2 = (p+3)a, ap = 2 S△ABC = 4S△BO