The first parentheses contain the cubed root of both the terms so x and y respectively. second parentheses follows the formula (a^2 + ab + b^2) x corresponds to a and y corresponds to b. The signs are what change depending on what the original equation is. Since the original is a subtraction then the signs are -/+/+. you can remember it using the acronym SOAP. (S = same, O = opposite, AP = always positive) So the first sign is x - y (same as subtraction from original), the second and third are x^2 + xy + y^2 (opposite is a plus, and the last sign is always a positive.
Step-by-step explanation: The question states that the change wasn't a positive one, it was a negative one as it states that the temperature changed an average of -2.250 Fahrenheit per hour. So, we multiply that by 3 to get -6.75. This is why A is correct.
