What is happening to this graph when the x vaules -1 and 1

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

Atype of plant is introduced into an ecosystem and quickly begins to take over. a scientist counts the number of plants after mmonths and develops the equation p(m)= 19.3(1.089)^m to model the situation. most recently, the scientist counted 138 plants. assuming there are no limiting factors to the growth of the plants, about how many months have passed since the plants werefirst introduced? a)o 6.1b)0.6.6c)10 72d)o 23.1