Question

What is the vertex of y=x2+4x−1

Answer 1

`vertex = (-2,-5)`

Explanation:

`y=x^(2) +4x-1\\\\y=x^2+4x+4-4-1\\\\y=(x+2)^2-5`

for

`y=(x-h)^2+c\\\\vertex = (h,c)`

in our equation we have

`h=-2\\\\c=-5`

so the vertex is

`(-2,-5)`

Answer 2

Explanation:

Vertex's x-coordinate = -b/2a = -4/2 = -2

Vertex's y-coordinate = (-2)² + 4(-2) - 1 = -5

Hence the vertex is (-2, -5).