consider the airing sequence -9,-2,5,12 given that the sequence is represented by the function f(n), what are the values of f(1) and the common difference

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).