Question

Find the equation of the axis of symmetry and the coordinates of the vertex of the graph of the function y = –2^2 +6x – 1.

A. x = 1.5;  vertex: (1.5, 3.5)
B.x 

= –1.5;  vertex: (–1.5, –5.5)
C.x  = 3;  vertex: (3, 35)
D.x  = –1.5;  vertex: (–1.5, – 14.5)

Answer 1

For a parabola, the axis of symmetry divides it into two congruent or identical halves. It passes through the vertex and is thus equal to the x-coordinate of the vertex. For given quadratic equation with a form y = ax^2 + bx - 1, the vertex (h,k) can be obtained using the formulas: h = -b/2a and k is determined by evaluating y at h. In this case, a = -2, b = 6, thus, h = 1.5, k = 3.5. So, the answer is choice A.