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Yes, negative feedback is the common method. Another way to think of it: We cause the inverting terminal to choose a bit of the incoming voltage, and a bit of the output. (It might be by resistor network, or various components). There is a certain voltage which the output then needs to create, to make the inputs equal.
Internally, the op amp must draw from either supply rail, and adopt a certain internal resistance, to create the appropriate voltage at the load.
For a good understanding of the feedback principle it is necessary, I think, to realize that the voltages at both inputs are NOT equal (due to negative feedback).
This is because the opamp always needs an input voltage difference to produce an output voltage.
However, due to the large open-loop gain Aol of the opamp this differential input voltage is so small (microvolts) that - in most cases - this voltage can be neglected if compared with all the other voltages in the circuit.
That means, during the calculation process we are allowed to ASSUME that both voltages are equal.
This assumption is identical with the assumption of a n IDEAL opamp (infinite open-loop gain Aol)
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