If a² + b² = 86 and ab = -16, find the value of (a - b)²

What is an additional type of erosion found at the coast? what does it mean?

Which two nations are doing the most to combat their environmental issues?

Which of the following statements does not describe shi huangdi? a. shi huangdi was the first emperor of the qin dynasty. b. shihuangdi wrote the lunyu, the most important text in confucianism. c. shihuangdi conquered city-states to unite china. d. shihuangdi began the process of building the great wall of china.