Which technique did bonnie use in this situation?
bonnie had 3 items in her shopping cart: a football for $14.99, towel for $8.68, and hairbrush for $10.50. sales tax is 7.75%. bonnie figures the total cost will be about $39.
choose the answer.
a.
mental math
b.
estimation
c.
number sense.

Cassie is traveling 675 miles today to visit her brother and his family. so far, she has stopped for gas three times. at the first stop, she put in 7.1 gallons of gas and paid $23.79. at her second stop, she put in 5.8 gallons of gas and paid $19.08. and, at the third stop, 6.6 gallons and paid $20.39. at which stop did casey pay the most for gas?

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)

Find the volume of the solid obtained by rotating the region enclosed by the curves y=1x and y=7^-x about the x-axis. (use symbolic notation and fractions where needed.) volume =