Extra exam question E7G09

WhyThe circuit in Figure E7-3 with R1 at 1,000 ohms, RF at 10,000 ohms, and 0.23 volts DC applied to the input produces an output voltage of -2.3 volts. In the Figure E7-3 inverting amplifier, output voltage equals negative RF divided by R1, times the input voltage: negative 10,000 divided by 1,000, or negative 10, times 0.23 volts works out to negative 2.3 volts, answer D. The gain magnitude alone (2.3 volts) without the sign, or the raw unamplified input voltage, don't reflect both the actual amplification and the phase inversion this inverting configuration applies.