Which of the following equations will result in a U-shaped graph? y = 2 x - 4
y = |-4 x|
y = 3 x2 - 5
y = -2 x3

In a quadratic function of the form ax^2+bx+c, which of the following is not true? a. the y-intercept is c. b. if a is positive, the parabola opens up. c. the vertex has an x-coordinate of -b/2a. d. the axis of symmetry is the line y=-b/2a.