The ratio of young people to adults was 7 to 5 If the total number of people is 1260 how many more young people than adults

How do you solving the solution of each system using elimination?

2people are trying different phones to see which one has the better talk time. chatlong has an average of 18 hours with a standard deviation of 2 hours and talk-a-lot has an average of 20 hours with a standard deviation of 3. the two people who tested their phones both got 20 hours of use on their phones. for the z-scores i got 1 for the chatlong company and 0 for talk-a-lot. what is the percentile for each z-score?

What is the absolute value of the complex number -4-sqrt2i