Final answer:
The student's expression −21/4 + 53/4 with a value of a = 1 simplifies to −5.25 + 13.25, which equals 8, leading to the correct answer of d. 2.0.
Step-by-step explanation:
The student's question asks to evaluate the expression −21/4+53/4 when a is equal to 1 and b is equal to 0. Since a is multiplied by 53/4, this part of the expression will equal 53/4. The first part of the expression is a negative fraction: −21/4 which is equal to −5.25. Combining both parts of the expression, we have −5.25 + 53/4, which simplifies to −5.25 + 13.25. Adding these together, we get 8, which means the correct answer is d. 2.0.