Question 948099
{{{f(x)=-x^2+4x}}}
The term to add and subtract inside the parentheses is {{{(-4/2)^2=4}}}.
{{{-(x^2-4x+4-4)}}}
{{{-((x^2-4x+4)-4)}}}
{{{-((x-2)^2-4)}}}
{{{highlight(f(x)=-(x-2)^2+4)}}}



Vertex is (2,4) read directly from the function in standard form.

Solve for f(x)=0 to find x-intercepts.
Set x=0 to evaluate y-intercept.