Operational Amplifier Math solve

 

Solution:

Redraw the circuit

Apply Voltage divider rule at node Vb :

Vb = (20*2)/ (20+2)

      = 1.82 V

At node Va we have,

(V1 – Va)/2 = (Va –Vo) /30

15V1 -27.3 = 1.82 – Vo

Vo = 14.12 V