Question

Determine the axis of symmetry and the vertex of the given function. y = 2x2 − 12x + 21

Answer 1

Ax^2+bx+c

A=2
B=12
C=21

a(x+d)^2+e

D=b/2a

D=12/2•2

D=2•6/2•2

Cancel the common factor
Then you’ll get
D= 6/2=3

E= c+b^2/4a
E=21-18
E=3

2(x+3)^2+3
A=2
H=-3
K=3

Answer: Vertex= (h,k)
=(-3,3)