There is a very long, complicated "back story" to this situation. At one time, public schools were funded by taxes collected from the local school district. So, for example, if you lived in the geographic area where the Fitzgerald Public School district administered the elementary and high school level of education, the local "school taxes" you paid annually went to fund the district. However, as years went by, it became apparent that some neighborhoods had more money than others. So folks living in the geographic area that funded Birmingham Public Schools had a much larger annual income (and thus paid more school taxes) than those living in the Detroit Public Schools district. So schools located in more affluent areas had the benefit of the newest textbooks and the latest technology, as well as being able to hire the best teachers (because they could offer higher salaries). Meanwhile, the schools in economically depressed areas struggled to get necessary classroom supplies and had a difficult time hiring qualified teachers, since they couldn't match the salaries being offered by the more affluent suburbs.
Eventually the state and federal government stepped in and initiated a "no child left behind" credo. Suddenly taxes that had been paid to the local school district were partially diverted into a state-wide fund to help bring inner-city schools up-to-date. Since the funding was based on a "need" basis, those schools with the lowest test scores were deemed to be those who needed state/federal assistance the most, and money was funneled to those schools.
Sadly, this process has not worked liked the bureaucrats expected...there are too many examples of inner-city school administrators using the funds to increase their salaries and pad their expense accounts without passing on the funds to the students....but that's a whole other story.