Based on the waveform for figure 1-2 and distorted waveform for figure 1-2, the output voltage decreases by 0.1V. It is the in figure 1-4. They are the same because both have common emitter. The only difference is RE. The figure 1-2 is larger the output voltage than the figure 1-4 because of the resistance in the emitter. Based on the waveform for figure 1-6 and distorted waveform for figure 1-6, the output voltage increases by 0.3V. While the figure 1-8 increases only by 0.1V. The figure 1-6 is voltage divider configuration while the figure 1-8 is collector feedback configuration. Hence, the voltage divider and collector feedback have the same the output voltage change. The frequency of output voltage of figure 1-2 and 1-4 is different from the figure 1-6 and 1-8. The figure 1-2 has the largest voltage gain while the figure 1-6 and 1-8 has the smallest voltage gain. The larger the voltage gain, the easier to be distorted and to cool down.