Today we reviewed the three forms of a quadratic function: vertex form, intercept form, and standard form. Vertex form is y = a(x - h)^2 - k where the vertex is (h, k) and the axis of symmetry is x = h. Intercept form (or factored form) is y = a(x - p)(x - q) where p and q are the x-intercepts. To find the axis of symmetry, find the average of the two x-intercepts. This is also the x-coordinate of the vertex. To find the y-coordinate of the vertex, substitute the x-coordinate back in to the equation and solve for y. Standard form is ax^2 + bx + c = 0. To find the vertex compute -b/(2a), then substitute that value in for x in the equation and solve for y to find the y-coordinate. The axis of symmetry will be x = -b/(2a). We also converted from intercept form to standard form by multiplying and also from vertex form to standard form.
HW is from your Math II book: p. 65 (13-24) Ignore the directions in the book, and just state the vertex and axis of symmetry and p. 66 (25-30) Convert to standard form.
