15. apply mathematics (1)(a) suppose you have a box with a 4 x 4-in.
square base and variable height h. the surface area of this box is a
function of its height. write a function to represent the surface area.
evaluate the function for h=6.5 in.

Aquantity with an initial value of 3900 decays exponentially at a rate of 35% every hour. what is the value of the quantity after 0.5 days, to the nearest hundredth?

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).

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10