Answer :
I believe the answer is either 5 or -1.5
4n - 7 = 13
7 - 4n = 13
4(5) - 7 = 13
7 - 4(-1.5) = 13
4(5) - 7 = 13
4n - 7 = 13
7 - 4n = 13
4(5) - 7 = 13
7 - 4(-1.5) = 13
4(5) - 7 = 13