When deciding to model a situation with 3d figures, what are the most important things to remember?

Abook store is having a 30 perscent off sale. diary of the wimpy kid books are now 6.30 dollars each what was the original price of the books

If f(x)= x^2 - 4 and g(x)=x^2 + 2 x, (b). (f-g)(x) i think i know the 1st 2 steps: f(x)-g(x) x^2-4 - x^2+2x

Drag each value to the correct location on the equation. not all values will be used. a company sells lab equipment. the daily revenue and costs are modeled by the functions below where x is the number of units sold. determine the function representing the total daily profit, p(x), after selling x units. 0.32 -0.32 -52 52 340 200