The resistors in the difference amplifier shown in Figure. 1 Ra = 24kΩ, Rb = 75kΩ, Rc = 13...

The resistors in the difference amplifier shown in Figure. 1 Ra = 24kΩ, Rb = 75kΩ, Rc = 130kΩ, Rd = 120 kΩ The signal voltages υa and υb are 8 and 5 V, respectively, and υCC = ±20 V.

a) Find υo.

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b) What   is the resistance seen by the signal source υa?

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c) What   is the resistance seen by the signal source υb?

Figure. 1