Help plz I don't know the answer plz really answer it

Write the sentence as an equation. 6 fewer than the quantity 140 times j equals 104

Mat bought a phone for $100. he has to pay $30 per mouth. if he has paid $640 in total, how many mouth has he had the phone?

If a suspect is in possession of 20 grams of cocaine how many ounces does he possess what will the charge be