Please help please ASAP

Nine more than four times a number is the same as one less than twice the number. find the number?

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).

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?