For this case we have the following function: y = 1/4 (x + 2) ^ 2 - 7 We derive the equation: y '= 1/2 (x + 2) Equaling zero we have: 1/2 (x + 2) = 0 We clear the value of x: x + 2 = 0 x = -2 Answer: The equation of the axis of symmetry for the parabola is: x = -2