Serial numbers for a product are to be made using 2 letters followed by 4 digits. The letters are to be taken from the first 7 letters of the alphabet, with no repeats. The digits are taken from the 10 digits (0, 1, 2, ..., 9), with no repeats. How many serial numbers can be generated?

Given the system of equations presented here: 2x + 4y = 14 4x + y = 20 which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? multiply the second equation by â’4 to get â’16x â’ 4y = â’80 multiply the second equation by â’1 to get â’4x â’ y = â’20 multiply the first equation by 2 to get 4x + 8y = 28 multiply the first equation by â’1 to get â’2x â’ 4y = â’14