So the derivative of y with respect to t is just dy dt. And then finally, right over here, the derivative of 10y with respect to t is the derivative of 10y with respect to y, which is just 10, times the derivative of y with respect to t, which is dy dt. And there you have it. You have your relationship between dx dt, dy dt, and x and y. So let's just make sure we have everything. This is what we're trying to solve for, dx dt. And let's see, we have another dx dt here.