So we're going to evaluate that at zero and at negative one. And to that we're going to add, so let's do this definite integral over here. The antiderivative of e to the negative four x, the antiderivative is going to be equal to negative e to the negative four x over four. And the way you realize that is, if this was just an e to the x, then its antiderivative would just be e to the x. If you have an e to the negative four x, then you know that whatever its antiderivative is, is going to be essentially an e to the negative four x. But when you take its derivative, you're going to have to take the derivative of the negative four x part because of the chain rule. And so you're going to have to have a negative four that comes out.