Prove that (R,+,.) and (Q,+,.) are fields

Alicense plate is to consist of 44 digits followed by 55 uppercase letters. determine the number of different license plates possible if the first and second digits must be? odd, and repetition is not permitted.

The median of a data set is the measure of center that is found by adding the data values and dividing the total by the number of data values that is the value that occurs with the greatest frequency that is the value midway between the maximum and minimum values in the original data set that is the middle value when the original data values are arranged in order of increasing (or decreasing) magnitude

Which of the following is the explicit rule for a geometric sequence defined a recursive formula of a -5a for which the first term is 23?