Factor this expression. 54 + 24 =

a. 4(9 + 6)
b. 9(6 + 4)
c. 78
d. 6(9 + 4)

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.