I need help with all of this

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible

Question 10 of 211 pointuse the elimination method to solve the system of equations. choose thecorrect ordered pair.10x +2y = 643x - 4y = -36a. (4,12)b. (-3, 11)c. (2,10)d. (-5, 8)

Ellen makes and sells bookmarks. she graphs the number of bookmarks sold compared to the total money earned. why is the rate of change for the function graphed to the left?