Vertex and Intercept Form Review

The vertex tells you the direction of the opening

The value of "a" tells you the direction of the opening.

All parabolas open upward

All parabolas open downward

(7 , 0) and (5 , 0)

(0 , 7) and (0 , 5)

(-7 , 0) and (-5 , 0)

(7 , 0) and (5 , 0)

(0, 0)

(2, 4)

(0, 0) and (0, 4)

(0, 0) and (4, 0)

y = (x-2)(x-1)

y = (x+2)(x+1)

y = (x+2)(x-1)

y= (x+1)(x-2)

undefined

1

2

-1

0

-1

1.5

-3

f(x) = - (x - 7)² + 1

f(x) = (x + 7)² + 1

f(x) = - (x - 1)² - 7

f(x) = (x + 1)² - 7

Parabola

Vertex

Axis of Symmetry

Roots

y = 2(x+3)² + 4

y = (x + 3)² - 4

y = (x - 3)² + 4

y = 2(x - 3)² + 4

roots or x-intercepts

parabola

axis of symmetry

line of dashes

(5, 2); opens up

(5, 2); opens down

(-5, 2); opens up

(-5, 2); opens down

f(x) = (x - 5)² + 1

f(x) = (x - 1)² - 5

f(x) = (x + 1)² - 5

f(x) = (x + 5)² + 1

y-intercept

any random point

vertex

symmetrical point for the vertex

(5, -4)

(-5, -4)

(-15, -4)

(15, -4)