If the axis of symmetry of the parabola y = AX2 + BX + C (a ≠ 0) is a straight line x = 2 and the minimum value is - 2, then the root of the equation AX2 + BX + C = - 2 about X is______ ．

If the axis of symmetry of the parabola y = AX2 + BX + C (a ≠ 0) is a straight line x = 2 and the minimum value is - 2, then the root of the equation AX2 + BX + C = - 2 about X is______ ．

Because if the axis of symmetry of the parabola y = AX2 + BX + C (a ≠ 0) is a straight line x = 2 and the minimum value is - 2, the vertex coordinates of the parabola are (2, - 2); when the root of the equation AX2 + BX + C = - 2 of X is y = - 2, the value of X is taken, so x = 2

Given that the two roots of the equation AX2 + BX + C = 0 (a ≠ 0) are X1 = 1.3 and X2 = 6.7, then the axis of symmetry of the parabola y = AX2 + BX + C (a ≠ 0) is______ ．

∵ the two roots of the equation AX2 + BX + C = 0 (a ≠ 0) are X1 = 1.3 and X2 = 6.7, the coordinates of the two intersections of the parabola and X are (1.3, 0), (6.7, 0), and the two intersections of the parabola and X axis are about the axis of symmetry of the parabola, and the axis of symmetry is x = X1 + X22 = 4

Given the curve y = 13x3 + 43, then the tangent equation passing through point P (2,4) is______ ．

∵ P (2,4) is on y = 13x3 + 43, y '= X2, k = 22 = 4. The linear equation obtained is y-4 = 4 (X-2), 4x-y-4 = 0. When the tangent point is not p, let the tangent point be (x1, Y1). According to the tangent passing through P, we can get: X12 = Y1 − 4x1 − 2 and Yi = 13x13 + 43, then we can get X1 = - 1, Yi = 1