Answer:
a. The temperature is ten degrees Fahrenheit below zero
b. The temperature is twenty two degrees Celsius below zero.
Explanation:
In the number line any number below zero is considered as negative and any number above zero is considered as positive.
The first sentence states it is −10 degrees Fahrenheit below zero. This statment makes no logical sense. Below zero is already considered negative there is no need to use the negative sign in this case.
The second sentence makes the same mistake but, here it is Celsius. It does not matter which scale is being used less than zero means negative no need to use the negative sign there.