Answer:
Explanation is the answer
Step-by-step explanation:
The max happens at the vertex. The line of symmetry runs through the vertex. So if you have the x-intercepts of the graph, the axis of symmetry will be the same distance from them but on opposite sides of the axis of symmetry. So if you have the x-intercepts then you can average them to fnd the x-coordinate of the middle point, the vertex.
So your factored form says the x-intercepts are (20,0) and (100,0).
So the x-coordinate of the vertex is (20+100)/2=120/2=60.
The question is asking for x-coordinate of the vertex so we are done.
