Question

Choose the equation below whose axis of symmetry is x = 0.

y = x2 + 2x
y = x2 − 16x + 58
y = x2 + 2
y = x2 − 4x + 2

Answer 1

i think the answer would be y =x2+2

Answer 2

The axis of symmetry of a parabola is a vertical line that divides the parabola into two congruent halves. The axis of symmetry always passes through the vertex of the parabola. The x-coordinate of the vertex of the parabola
`y=ax^2+bx+c` can be found as

`x_v=-(b)/(2a).`

The equation x=0 represents the y-axis, therefore, parabola should be symmetric about the y-axis. This means that parabola vertex is placed on the y-axis. If parabola vertex is placed on the y-axis, then
`x_v=0` and

`-(b)/(2a)=0\Rightarrow b=0.`

Only third parabola has b=0, then

correct choice is C.