What is the vertex and y-intercept of f(x)=-(x-1)(x-5)

Question

What is the vertex and y-intercept of f(x)=-(x-1)(x-5)

Answer 1

 

f(x)= -x² +6x - 5

 

Vertex { -(6)/2(-1) ; f(3) } ----> Vertex ( 3 ; -9+18-5 )

 

Vertex (3 ; 4)

 

y-intercept (0 ; -5)