Which is the equation of a hyperbola with directrices at x = ±2 and foci at (4, 0) and (−4, 0)? (i know its not b) x squared over 8 minus y squared over 8 equals 1
x squared over 8 minus y squared over 16 equals 1
y squared over 8 minus x squared over 8 equals 1
y squared over 16 minus x squared over 8 equals 1

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?

Question 1 of 10 2 points different groups of 50 graduates of an engineering school were asked the starting annual salary for their first engineering job after graduation, and the sampling variability was low. if the average salary of one of the groups was $65,000, which of these is least likely to be the average salary of another of the groups? o a. $64,000 o b. $65,000 o c. $67,000 o d. $54,000

Solve for b. ab + c= d b= a + old ob=allc-ch b= (d-c/a