Whats 12+3x^3-x in standard form and what is the leading coefficient

Because of your favorite lemonade it is $3.84 for 3 gallons. write this as an unit rate

Prove that the sum of two consecutive exponents of the number 5 is divisible by 30.if two consecutive exponents are 5n and 5n + 1, then their sum can be written as 30.

Problem fathi wants to print out a pdf document that is 48 pages long. to save paper, he decides to print on both sides of each sheet and to print two pages on each side of the sheet. how many sheets of paper will he need?