Nine times a number added to -5 subtracted from twice the sum of nine times a number and two

Let's denote a variable to the number as x. Then, let's slowly decipher the verbal descriptions into algebraic expressions:

Nine times a number added to -5: 9x + ⁻5  = 9x - 5
twice the sum of nine times a number and two: 2(9x+2)

Let's subtract the first expression to the second expression:
2(9x+2) - (9x - 5)
Next, let's simplify the expression.

18x + 4 - 9x + 5
9x + 9

The final expression would be 9x + 9, or nine times a number added to nine.

She should use 12/3 to measure