Question 930050
y = x^2-4x-5  (x = 0)...y=intercept:  -5
0 = (x+1)(x-5)
x-intercepts: -1, 5
.......
y = x^2-4x-5 (Completing the Square)
y = x^2-4x+4 -4 +5 = (x-2)^2 - 4 - 5
y = (x-2)^2  - 9  V(2,-9)
......
f(6) = (6)^2 - 4(6) - 5 = 7
.....
the vertex form of a Parabola opening up(a>0) or down(a<0), 
{{{y=a(x-h)^2 +k}}} 
where(h,k) is the vertex  and  x = h  is the Line of Symmetry 
.....
{{{drawing(300,300,   -10,10,-10,10,  blue(line(2,10,2,-10))  ,  
 grid(1),
circle(2, -9,0.4),
circle(6,7,0.4),
circle(0, -5,0.4),
circle(-1, 0,0.4),
circle(5, 0,0.4),
graph( 300, 300, -10,10,-10,10,0, x^2-4x-5))}}}