Solve each problem. 1. One way to master the rules for the order of operations is to insert symbols within a display of numbers in order to obtain a predetermined result. For example, the display 444 4 can be used to obtain the result 8 as follows (by inserting in symbols): (4+4)+4:4 Using only the symbols +, -, x, +, () , represent each of the following numbers with four 4's. 12 = 15 = 16 = 17 = 20 =2. Determine r and a, for the geometric sequence with a, = 24 and as = 648. 3. Many people have no idea of the difference in size between a million (1,000,000), a billion (1,000,000,000), and a trillion (1,000,000,000,000). a. Write a million, a billion, and a trillion in scientific notation. b. Determine how long it would take to spend one million dollars if you spent $1000 a day. c. Determine how long it would take to spend one billion dollars if you spent $1000 a day. d. Determine how long it would take to spend one trillion dollars if you spent $1000 a day. e. How many times greater is one billion dollars than one million dollars