I need help on 4-4a please

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).

Suppose your school costs for this term were $4900 and financial aid covered 3/4 of that amount. how much did financial aid cover? and how much do you still have to pay?

Define multiplicative inverse. give an example of a number and its multiplicative inverse.