Question

Opens up or down, Vertex: (-10, -1), Passes through: (-8, -5)

Answer 1

opens down

Explanation:

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

Here (h, k) - (- 10, - 1 ) , then

y = a(x + 10)² - 1

To find a substitute (- 8, - 5) into the equation

- 5 = a(- 8 + 10)² - 1 ( add 1 to both sides )

- 4 = a(2)² = 4a ( divide both sides by 4 )

- 1 = a

y = - (x - 10)² - 1 ← equation in vertex form

To determine if it opens up/ down consider the value of a

• If a > 0 then curve opens up

• If a < 0 then curve opens down

Here a = - 1 < 0 then curve opens down