If R₃ opens in the given circuit, the total resistance (R_T) between points A and B equals ____.

___ is often used to analyze multiple-source circuits.

In the given circuit, the voltage dropped across R₁ equals _____.

If four 10 k resistors are in series with a single 20 k resistor and one of the parallel resistors shorts, the voltage across the other parallel resistors ________.

Series components in a series–parallel circuit may be in series with other _______________ components, or with other _______________ components.