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When the internal and external resistances are equal, the output power of the power supply is the maximum. As can be seen from the image, when the resistance R = 5Ω, the maximum output power of the power supply is 45W, so the internal resistance of the power supply is 5 Ω;

According to P=I2R=(ER+r)2R, there are:

45=(E5+5)2×5, and the solution is: e = 30v.

So the answer is: 5,30.