Question

如图,已知抛物线y等于x的平方减ax加a加2与x轴交于A、B两点,与y轴交于点D（0,8）,直线DC∥x轴,交抛物线与另

Answer 1

抛物线方程y = x^2 - 6x + 8 = (x-2)(x-4)A(2,0),B(4,0),C(6,8)PC = 2t, AQ = t, DP = 6-2t, DP = OA+AQ, 6-2t = 2+t, t = 4/3S-PQBC = 1/2 OD * (PC+QB) = 4 * (2t + 2-t) = 4*(2+t) = 14, t = 3/2