At first glance, this looks quite tricky, as usually when we are asked to find dy/dx, we have one equation, but here we have 2.So in this case, we need to use the statement that dy/dx = (dy/dt) * (dt/dx)Then, we just need to find dy/dt and dy/dx.dy/dt = -2/t^2dx/dt = -4, and therefore dt/dx = -1/4So, (dy/dt)(dt/dx) = (-2/t^2)(-1/4)= 1/2t^2.