a + bi To divide two complex numbers: we multiply it with: (select the best answer.) c + di с — di с — di c + di c + di а — bi а — bi c + di с — di To Solve a quadratic equation, a · solution be complex numbers? x2 + c = 0, where a and c are nonzero real numbers. When will the > 0 a < 0

In a traditional class with in-class tests, a question that is often asked after a class exam is, "What was the class average?" If that question is asked and the professor says that the class average was 80, what information do the students gain by knowing that? I want you to focus on both what the individual students knows about their own grade as well as what the students know about the class's grades on that exam.

In 2004 it surfaced in Reader's Digest presented as having happened to a teacher at an unnamed community college. Four students walked in halfway through American history test my father was giving at the local community college. "Sorry," they said, "we had a flat tire." An understanding man, Dad said that if they could answer just one question correctly, he would give them each an "A" for the exam. The students agreed. So my father handed each one a piece of paper, placed them in four separate comers and said, "Write down which tire was flat." Kurt Smith What is the probability that these four students would give identical answers if they hadn't had a flat tire? Why?

suppose we have the following numbers  5,8,12,3 and 4 we want to add one more so that the mean of all the values will be 9. what number should be added