What Is The Vertex, Quadratic Function In Standard Form, Axis Of Symmetry, X-intercepts Of The Following Function?

F(x)= -4x²-8x+12

For finding the Vertex of the equation:

y - 12 = -4(x²+2x)

y - 12 = -4(x²+2x+1-1)

y - 12 = -4{(x²+2x+1)-1}

y - 12 = -4{(x + 1)²-1}

y - 16 = -4(x + 1)²

Vertex = (1,-16)

The standard form:

The standard form of parabola is y - 16 = -4(x + 1)²

Axis of symmetry:

Axis of symmetry in this equation is -1.

For x-intercept:

Put y = 0 for x-intercept therefore,

0 - 16 = -4(x + 1)²

4 = (x + 1)²

Taking square root on both sides:

2 = x + 1

x = -1