Can someone explain This and would this be linear combos or multiplying monomials

The expression represents the profit is 33x + 390 ⇒ D

Step-by-step explanation:

Let us solve the question

∵ Profit = revenue - cost

∵ The revenue, in dollars, of a company that makes skateboards can be

    modeled by the polynomial 2x³ + 30x - 130

∴ Revenue = 2x³ + 30x - 130

∵ The cost, in dollars, of producing the skateboards can be modeled by

   the polynomial 2x³ - 3x - 520

∴ Cost = 2x³ - 3x - 520

→ Use the rule above to find the profit

∵ Profit = 2x³ + 30x - 130 - (2x³ - 3x - 520)

→ Remember (-)(-) = (+)

∴ Profite = 2x³ + 30x - 130 - 2x³ + 3x + 520

→ Add the like terms

∵ Profit = (2x³ - 2x³) + (30x + 3x) + (-130 + 520)

∴ Profite = 0 + 33x + 390

∴ Profit = 33x + 390

∴ The expression represents the profit is 33x + 390

b) 1/3 * 1/5

step-by-step explanation:

each smallest part is 1/15 since the written one is 1/5 and it's divided by 3 equal parts. (1/5 )/3 = 1/15 = 1/3 * 1/5

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)