Answer:
A.
Step-by-step explanation:
A line adds up to equal 180 degrees. And adjacent angles also add to equal 180 since they share a side on a line. So add them together and make them equal 180
9x - 7 + 8.5x + 4 = 180
17.5x - 3 = 180
17.5x = 183
x = 10.5
Can you show the answer choices but I believe is 18
One of the product rules for exponents was used.

Or, you can consider that the definition of an exponent and the associative and commutative properties of multiplication were used.
Her answer represents "-3.7 less than 4 times a number is 11.9". The correct equation should be -3.7n-4=-11.9.