Question

How do you identify the important parts of `y = (x – 1)^2 – 16` to graph it?

Answer 1

Minimum point `rArr` `(1, -16)`
`y-`intercept `rArr` `(0, -15)`

Explanation:

From the completed square, you already know that the minimum points are `(1, -16)`

To find the `y-`intercept, you need to expand the brackets to get it in the form of `ax^2 + bx+c` , where `c` is your `y-`intercept.

So,

`(x-1)(x-1) -16`
= `x^2-x-x+1-16`
= `x^2-2x+1-16`
= `x^2-2x+15`

So `15` is your `y-`intercept.

graph{(x-1)^2-16 [-9.495, 10.505, -17.76, -7.76]}