Completely factor 4a²b - 12ab³ please explain

Apark is in the shape of a rectangle. the park authorities are planning to build a 2-meter-wide jogging path in the park (shown as the shaded region in the image). what is the area of the jogging path? plz

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply