PNAS is the world's most-cited multidisciplinary scientific serial. It publishes high-impact research reports, commentaries, perspectives, reviews, colloquium papers, and actions of the Academy. In ...

Removing brackets is to multiply the term outside the brackets by each term inside - also known as the distributive law. Use FOIL to remove a pair of brackets then simplify by collecting like terms.

Many students begin school with a love of math, but stumble when they reach algebra. With the increasing prevalence of mobile learning, though, on-demand apps and resources can help students stay on ...