the axis of symmetry for a function in the form f(x)=x^2+4x-5 is x=-2. what are the coordinates of the vertex of the graph?

Respuesta :

hello : 
f(x)=x²+4x-5
The axis of symmetry for a function in the form f(x)=x^2+4x-5 is x=-2 :
f(x) = (x+2)² + b 
f(x) x²+4x+4+b=  x² +4x-5 
 4+b= -5 
b = -9
the vertex is : (2 , -9)