6TH GRADE MATH I RLLY NEED HELP

Aculture started with 3000 bacteria. after 5 hours it grew to 3900 bacteria. predict how many bacteria will be present after 9 hours

Combine like terms to make a simpler expression 3z+z

Carli has 90 apps on her phone. braylen has half the amount of apps as theiss. if carli has three timesthe amount of apps as theiss, how many apps does braylen have? let b represent the number of braylen's apps and t represent the number of theiss's apps.