What multiplies to be 25 and adds to be -10

Irene bought 3 yards of fabric and a spool of thread for $28.10. if the spool of thread cost $1.25, how much did the fabric cost per yard?

When y’all answer can y’all explain too !

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?