\fThis graph shows the number of U.S. elementary and secondary school students who were enrolled in private schools. (Source: U.S. Department of Education, National Center for Education Statistics, 2011 http://nces.ed.gov) Give the time intervals (if there are any) over which the rate of change of the function is positive. Type 'none' in each entry if no interval exists, or in the second set of entries if the second interval does not exist. Give intervals in increasing order. Enter your answers as integer numbers. The rate of change of the debt function is positive from The rate of change of the debt function is also positive from to . to . Give the time intervals (if there are any) over which the rate of change of the function is negative. Enter your answers as integer numbers. Type 'none' in each entry if no interval exists, or in the second set of entries if the second interval does not exist, and similarly the third set of entries. The rate of change of the debt function is negative from to . Give intervals in increasing order. The rate of change of the debt function is also negative from to . The rate of change of the debt function is also negative from to