From the problem statement:
n = "a number"
seven less than twice a number is -1
now i'll underline the changes made by interpreting the way the question was written:
7 less than two times n is -1
7 less than 2n equals -1
take away 7 from 2n = -1
2n take away 7 = -1
2n - 7 = -1
2n - 7 = -1
answer is: (A)
