Answer:
r = 5
Explanation:
The zeroes ( where the function intersects the x - axis) are equi-distant from the vertex line of symmetry
vertex 2,4 to get to -1 , 0 you have to go three units in the negative x direction ..... the other zero is on the OTHER side of the vertex 3 units which would be 5,0 so r = 5
Here is a graph to look at: