Tony’s investments lost $12,545.50 in value over the past 2.5 months. On average, how much did his investments change each month

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

Which shows the correct substitution of the values a, b and c from the equation 1=-2x+3x^2+1

Alex took his brother to a birthday party. the party was scheduled to last for 1 and 3/4 hours but they stayed for 4/5 of an hour more. how long did she stay at the party?