Answer: 1 degree Fahrenheit
Explanation:
The temperature starts at -10 degrees F, so if in two hours, the temperature has risen by 4 degrees, then the new temperature is -10 + 4 = -6 degrees F. 3 hours later, the temperature has risen another 7 degrees, so the new temperature is -6 + 7 = 1 degrees F. "addition equation" is ambiguous without knowing what class you are taking, but one such equation to represent the situation could be T = -10 + 4 + 7 = 1.