Ireally need with this algebra problem (reward: 98 pts.) i ordered some books online for myself and friends. each book costs $13 and the store charges a flat rate for shipping of $20. write an expression for the cost of buying n books.

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).

Asystem of equations has 1 solution.if 4x-y=5 is one of the equations , which could be the other equation ?

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16