So let's see, step one for Avery. She took, she's separately taking the derivative of seven and separately taking the derivative of five x. So this is, my spider sense is already going off here. Because what happened to this negative right over here? So it would have made sense for her to do the derivative of seven, and she could have said minus the derivative of five x. That's one possibility that she could have done. The derivative of a difference is equal to the difference of the derivatives.