So I'm assuming you've had a go at it, so let's work through this together. So that's y one. So the first derivative of y one, well, this is going to be, let's see, we just have to do the chain rule here, derivative of negative 3x with respect to x is just negative three, and the derivative of e to the negative 3x with respect to negative 3x is just e to the negative 3x. And if we take the second derivative of y one, this is equal to, same exact idea, derivative of this is negative three times negative three, it's going to be nine e to the negative 3x. And now we can just substitute these values into the differential equation or these expressions into the differential equation to verify that this is indeed going to be true for this function. So let's verify that. So let me, so we first have the second derivative of y, so that's that term right over there.