You can put this solution on YOUR website!
the equation is 4x - x^2 which is the same as -x^2 + 4x
this is a quadratic equation.
if the coefficient of the x^2 term is positive, the graph has the closed end down and the open end up.
if the coefficient of the x^2 term is negative, the graph has the closed end up and the open end down.
as seen on the graph, this equation has the closed end up and the open end down.
the closed end contains the minimum / maximum point of the quadratic equation.
that is found by the formula:
x = -b/2a
note the general form of a quadratic equation gets you:
a = coefficient of x^2 term
b = coefficient of x term
c = constant term
in your equation of -x^2 + 4x, you get:
a = -1
b = 4
c = 0