We have to find the parameter a so that (-1,2) is part of the function f(x) = ax²+4.
To check if a point is part of a function, we can replace the values of x and y = f(x) with the coordinates of the point and then, if the equation stays true, then the point is part of the function.
So for (x,y) = (-1,2) to be part of the function y = f(x), this equation has to stands true:
Then, the function would have to be f(x) = -2x² + 4.
We can check with a graph as:
Answer: a = -2
