T-shirts at Perfect Tee cost either $9 or
$10 depending on the style. Bella bought
13 t-shirts for a total of $124. How many
t-shirts of each price did she buy?

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).