Final answer:
The operation performed in the second step as per the given algebraic expressions is subtraction. No other operations are indicated in the given context, and the problem adheres to the order of operations acronym PEMDAS or BODMAS.
Step-by-step explanation:
You are asking which operation is performed in the second step of the problem based on order of operations. The expressions provided are D = A - B and D = A - B = 1.7. It appears that the original operation is subtraction, as indicated by the minus (-) sign between A and B.
When working with order of operations, recall the acronym PEMDAS or BODMAS, which stands for Parentheses/Brackets, Exponents/Orders, Multiplication, Division, Addition, and Subtraction. Following this rule, operations are performed in the following sequence: anything in parentheses first, followed by exponents, then multiplication and division from left to right, and finally addition and subtraction from left to right.
In the given problem, although we don't have the full context, there is no other operation except subtraction indicated between A and B. Therefore, the answer is A.) subtraction.