What does the exsppression represent

The graph below shows the amount of money left in the school’s desk fund, f, after d desks have been purchased. for each new desk that is purchased, by how much does the amount of money left in the school’s desk fund decrease?

Which verbal expression best describes the algebraic expression 3x ÷ 5? the quotient of three times some number and five the product of some number and five divided by three the quotient of three and some number times five the sum of three and some number divided by five

Factor 15x^3 - 5x^2 +6x-2 by grouping. what is the resulting expression