What is the answer to 14<-8+z what is Z?

Lisa has three classes that each last 50 minutes. what is the total number of minutes of the three classes

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.

Ineed with question three. i don't understand how i'm supposed to achieve 3 marks.