Question

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

Answer 1

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

Answer 2

x= -1
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