Factor 4x^2+81 over the set of complex numbers

The expression 42 plus 57 shows how much money nate spent at a store .which expression also shows how much money nate spend

What could explain what happened when the time was equal to 120 minutes

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).