I have no idea how to do this one please help

Each month, a shopkeeper spends 5x + 14 dollars on rent and electricity. if he spends 3x−5 dollars on rent, how much does he spend on electricity? for which value(s) of x is the amount the shopkeeper spends on electricity less than $100? explain how you found the value(s).

Yesterday, george drank 1 small bottle and 2 large bottles, for a total of 1,372 grams. the day before , he drank 1 small bottle and 1 large bottle, for the total of 858 grams. how many grams does each bottle hold?

The polynomial 2x3 + 9x2 + 4x - 15 represents the volume in cubic feet of a rectangular holding tank at a fish hatchery. the depth of the tank is (x – 1) feet. the length is 13 feet.