What is the domain and range of y=-3tan(1/2x)? Please help!

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?

Celeste wants to have her hair cut and permed and also go to lunch. she knows she will need $50. the perm cost twice as much as her haircut and she needs $5 for lunch. how much does the perm cost?

The weight v of an object on venus varies directly with its weight e on earth. a person weighing 120 lb on earth would weigh 106 lb on venus. how much would a person weighing 150 lb on earth weigh on venus?