Question

Write a quadratic function in standard form whose graph passes through the points (-8,0), (-2,0), and (-6,4)..

Answer 1

-0.5x^2 - 5x - 0.8

Explanation:

The 2 zeroes of the function are at x = -8 and x = -2 so we can write the quadratic as

y = a(x + 2)(x + 8) where a is a value to be found.

When x = -6, y = 4 so:

4 = a(-6+2)(-6 + 8)

4 = -8a

a = -0.5

The function is:

-0.5(x + 2)(x + 8)

= -0.5(x^2 + 10x + 16)

= -0.5x^2 - 5x - 0.8