So first, we want to figure out the derivative of x with respect to time. So the derivative of x with respect to time. So the derivative of the first thing times the second thing times y, plus just the first thing times the derivative of the second thing. 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.