The median weight of a boy whose age is between 0 and 36 months can be approximated by the function w(t)=7.42+1.92t−0.0074t2+0.000446 t3​, where t is measured in months and w is measured in pounds. Use this approximation to find the following for a boy with median weight in parts ​a) through ​c) below. a) The weight of the baby at age 7 months. The approximate weight of the baby at age 7 months is lbs. (Round to two decimal places as needed.) b) The rate of change of the baby's weight with respect to time at age 7 months. The rate of change for the baby's weight with respect to time at age 7 months is approximately lbs/month (Round to two decimal places as needed.)