Find the axis of symmetry for this parabola y=-5x^2-10x-15 write it as an equation

Axis of symmetry is the x value of the vertex

the x value of the vertex, in form

y=ax^2+bx+c is - b / (2a)

so

y=-5x^2-10x-15

a=-5

b=-10

x value of vertex is - (-10) / (2*-5) = 10/-10=-1

x=-1 is axis of symmetry

X = - 1

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