I'm trying to figure out how my book came up with it's answer. I've worked and reworked this but come up with anything but their answer. Here's what I'm trying to accomplish.

Evaluate the expression:

y^4 - y^3 + y^2 + 2y - 1

Let y = -1

I interpreted it to read:

-1^4 + -(-1)^3 + (-1)^2 + 2(-1) + (-1)

-1 + (1) + 1 +(-2) + (-1)

-1 + 2 + (-2) + -1

1 + -3

-2

The book says, "0" but I get "-2"

I'd like to see what you might evaluate it to.

Thanks!