Question

The vertex is 2,-4 what is the parabola equation

Answer 1

y = x² - 4x

Explanation:

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k ) are the coordinates of the vertex and a is a multiplier

Here (h, k ) = (2, - 4) , with a = 1 , the equation is

y = (x - 2)² - 4 ← expand using FOIL

= x² - 4x + 4 - 4

y = x² - 4x ← equation of parabola

Answer 2

y + 4 = (x - 2)^2

Explanation:

The vertex form of the equation of a vertical parabola is

y - k = a(x - h)^2, where (h, k) represents the vertex and a is a scaling factor which stretches or compresses the parabola vertically. If all we know is the vertex (2, -4), then the desired equation is:

y + 4 = a(x - 2)^2

If there is no vertical stretching or compression, then the equation becomes:

y + 4 = (x - 2)^2