Ernesto tried to determine the solution for the system of equations using substitution. his work is shown below. x – y = 7 3x – 2y = 8 step 1: x = y + 7 step 2: 3(y + 7) – 2y = 8 step 3: 3y + 7 – 2y = 8 step 4: y + 7 = 8 step 5: y = 1 in which step did ernesto make the first error?

According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. suppose that in a recent sample of 1500 shoppers, 315 stated that they prefer to buy generic instead of name-brand products. at a 5% significance level, can you conclude that the proportion of all shoppers who currently prefer to buy generic instead of name-brand products is higher than .18? use both the p-value and the critical-value approaches.