
Answer:
x = 7
Step-by-step explanation:
The line of symmetry is a vertical line passing through the vertex of the parabola with equation
x = c ( c is the value of the x- coordinate of the vertex )
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k ) are the coordinates of the vertex and a is a multiplier
y = - 2(x - 7)² + 11 ← is in vertex form
with (h, k ) = (7, 11 ) with h = 7
Equation of axis of symmetry is then x = 7