Answer:
Explanation:
If the problem was supposed to be "3.4 + 2.8d + 2.8d -1.3". Then the answer would be 5.6d + 2.1. you can combine the "d" terms because they have the same variable and you can combine the number terms because they are like. This result in 2.8d+2.8d + 3.4 - 1.3. This simplifies to the correct answer given above.