Question 1125443
the equation is y = ax^2.


when x = 2, y is equal to -4.


therefore -4 = a * 2^2 which becomes -4 = a * 4.


solve for a to get a = -4 / 4 = -1.


the equation becomes y = -1 * x^2 which is written as y = -x^2.


here's the graph.


<img src = "http://theo.x10hosting.com/2018/100702.jpg" alt="$$$" >


the blue line is the graph of the equation.


the orange line is used to show the intersection of the graph with x = 2.


the intersection is the point (2,-4).


this says that the value of y is equal to -4 when the value of x is equal to 2.