The vertex of this parabola

y=-5x^2-10x-13

2 ways:

1. hackway

2. convert to vertex form

hack way is

for

y=ax^2+bx+c

the x value of the vertex is - b/2a

plug that value in to get y value

y=-5x^2-10x-13

a=-5

b=-10

xvaluevertex = - (-10) / (2*-5) = 10/-10=-1

xvalue=-1

sub back

y=-5 (-1) ^2-10 (-1) - 13

y=-5 (1) + 10-13

y=-5+10-13

y=-8

xvalue=-1

yvalue=-8

vertex = (-1,-8)

or convert to y=a (x-h) ^2+k where (h, k) is vertex

y=-5 (x^2+2x) - 13

y=-5 (x^2+2x+1-1) - 13

y=-5 ((x+1) ^2-1) - 13

y=-5 (x+1) ^2+5-13

y=-5 (x+1) ^2-8

y=-5 (x - (-1)) ^2 + (-8)

vertex is (-1,-8)