non-inverting op-amp with reference voltage on negative feedback?
One simple approach, if you are familiar with standard op amp circuits, is to use superposition.

First, assume that OUT-DAC1 is connected to ground but that REF-2V5 is still attached. What is the output of the op amp?

Second, assume that OUT-DAC1 is still attached but that REF-2V5 is connected to ground. What is the output of the op amp, as a function of OUT-DAC1?

Add the two results and you have your answer.