Find the sum. Express the answer in scientific notation. (8.7 times 10 Superscript 9 Baseline) + (4.58 times 10 Superscript 9 Baseline)

Adriano loves anime and collects toys from his favorite series.each month he gains 4 toys. if adriano has 3 toys when he starts collecting, how many does he have after 4 months

Find the value of the cosine for angle a

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?