Please answer D and E

c) Given V d) Given yz? = x2 - 21, find dz/dt when x = 1, y = -5 and z = 2 if dx/di = 3 and dy/di = -2. e) Given (x+ y) + x= 3, find dy/di when x = 2 and y - -3 if dx/dt = 4. ( 2X+zy )(It * )+ 3. As a spherical snowball rolls down a hill it gains 12 cm Xs of snow. Find how quickly the radius when r = 8cm