Which of the following expressions are perfect-square trinomials? Check all of the boxes that apply. x2 – 16x – 64

4x2 +12x + 9

x2 + 20x + 100

x2 + 4x + 16

Can someone me and do the problem plz so i can understand it more better

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?

Pranza plotted point a in the coordinate plane below.