Question

What is the axis of symmetry of `y=2(x+1)^2-1`?

Answer 1

`x = -1, forall y in RR`

Explanation:

The axis is the vertical straight line `x = x_v = -b/(2a)`,
if the parabola is `y = ax^2 + bx + c`

`y = 2(x^2 + 2x + 1) - 1`

`y = 2x^2 + 4x + 1 => a = 2 , b = 4`

`x_v = -4/4`