Which elementary row operation will reduce the x–element in row 2 to 0 in this matrix? 1 1 1|12 2 1 0|14 2 0 3|19

Given the following sampling distribution of one mean with a sample size 49, from a normally distributed population,find the population standard deviation, o.79828588912497

How do i do this activity, is appreciated

Okay so i didn't get this problem petro bought 8 tickets to a basketball game he paid a total of $200 write an equation to determine whether each ticket cost $26 or $28 so i didn't get this question so yeahyou have a good day.