y= -2(x-1)^2 - 5
A.) Identify the coefficients (a, h, and k)
B.) Tell whether the graph opens up or opens down.
C.) Find the vertex. Write as a coordinate.
D.) Find the axis of symmetry. Write as an equation.
E.) Find two more points on the graph. You can choose what x - values to use. Write your points as coordinates (x, y).
Part a) we have a quadratic equation (vertical parabola) written in vertex form
y=a(x-h)^2+k
where
a is the leading coefficient
(h,k) is the vertex
in this problem
a=-2
(h,k)=(1,-5)
so
h=1
k=-5
Part b) the graph open downward (because a is negative)
Part c) the vertex is the point (1,-5) see the part a
Part d) Axis of symmetry
the axis of symmetry of a vertical parabola is equal to the x-coordinate of the vertex
so
x=h
we have
h=1
therefore
x=1
Part e) Find two points
For x=0
substitute
y= -2(0-1)^2 - 5
y=-7
First point (0,-7)
For x=1
y= -2(1-1)^2 - 5
y=-5
the second point is (1,-5) -----> is the vertex
For x=2
y= -2(2-1)^2 - 5
y=-7
the point is (2,-7)