Can someone amswer this with an explanation so i know how to answer similar questions? ?

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).

Atransformation t : (x,y) (x-5,y +3) the image of a(2,-1) is

How can constraints be used to model a real-world situation?