SOLVE each system of equations below by substitution 1. y = -3x – 16 and 5x – 2y = -23
2. 6y – 3x = -9 and x = -2y + 5
3. y + 4 = 3x and 2y – 6x = -8

100,000 random people were tested for condition a. roberto's doctor told him he tested positive for condition a. if the test is 99% accurate and condition a is rare—one out of every thousand people have it. what is the probability that testing positive means roberto has condition a? 99.0% 1% 9% 99.9%