OpAmp - Inverting Summing Amplifier

In this configuration the OpAmp works as a inverting summing amplifier. Output: Vout = -((Rf/Rg1)*V1 + (Rf/Rgn)*Vn) If Rf is equal to Rg's: Vout = -(Rf/Rg)*(V1 + Vn) Ps.: Rf is the resistor in the feedback loop