Answer:
x = - 2
Explanation:
The axis of symmetry passes through the vertex, is a vertical line with equation equal to the x- coordinate of the vertex, that is
equation of axis of symmetry is x = 1
The zeros are equidistant from the axis of symmetry, on either side
x = 4 is a zero and is 3 units to the right of x = 1, so
3 units to the left of x = 1 is 1 - 3 = - 2
The other zero is therefore x = - 2