find y intercept and vertex math

Question

Consider the following equation:

f(x)=4-x²-8x

1)    Find the y-intercept.

2)    Find the vertex.

Answer 1

Hello Waker.

1) when Find the y-intercept just plug 0 for x; y = 4 - 0^2 -8*0 = 4

2) when Find the vertex follow these:

1. Get the equation in the form y = a*x^2 + b*x + c.
2. Calculate -b / 2a. This is the x-coordinate of the vertex.
3. To find the y-coordinate of the vertex, simply plug the value of -b / 2a into the equation for x and solve for y.

if you need more assistance please let me know