If you are working with time or days, you can't put in a negative value because if you are doing an experiment, you can't go back in time to do that experiment to gather data. (Time for the most part considered to be an input value so that's why I used it as an example.)
Answer:

Step-by-step explanation:
Given the diagram, we can see that ∠PQR and ∠RQS are complementary angles.
*Two angles with measures that add up to 90° are known as Complementary angles.*
Therefore, m∠PQR+m∠RQS=90°


Subtract 48 from both sides:


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