Question

F(x)=x^2+6x+8 What are the zeroes of the function? Write the smaller x first, and the larger x second

Answer 1

To find the zeros, set the function equal to 0. In other words, solve f(x)=0.

f(x) = 0

x^2 +6x + 8 = 0

(x+4)(x +2) = 0

x = -4 and x = -2

The vertex will happen when x = -b/2a:

`x=(-6)/(2(1)) = -3`
Then use this x-value of –3 to find the y-value of the vertex:

y = (-3)^2 + 6(-3) + 8 = 9-18+8 = -1

The vertex is (-3,-1).

Side note: The x-value of the vertex can also be found by finding the average of the two zeros:

(-4 + (-2)) / 2 = -6/2 = -3