Which addition does the model below represent? 3 + (negative 1)
3 + 4
3 + (negative 4)
3 + 1

The correct answer is 3 + -4.

Step-by-step explanation:

First the arrow begins at 0 and moves to the right 3 spaces positive, ending at 3. Then it moves backwards, which is subtracting left 4 spaces towards -1 past zero. When adding a negative to a positive, you convert it to subtraction. 3 + -4 is the same as 3 - 4. We know 4 - 3 normally is 1, but the other way around, since 4 is more than 3, we go one extra space negative to -1. Therefore, 3 + -4 is the answer.

the solution is 12x-6y