Operational Amplifiers
You obviously have DC input +1V at the left. To get the calculated output -10V you must have negative supply voltage connected to the opamp. There are many designs which are valid only when one has dual power supply. The negative side here will sink the the output current through the output transistors inside the opamp.

Phase inversion is same as multiplying by minus one. That's useful with sinusoidal AC signals. Your amp circuit as a whole will generate phase inversion and voltage gain=10. As well one can say "voltage gain=-10")