Calculate the current, with direction, through E$1,$ I$1.(5$ pts$.)$ b$.$ Calculate the current, with direction, through E$2,$ I$2.(5$ pts$.)$ c$.$ Determine the voltage, Vab. $(5$ pts$.)$ d$.$ Determine the voltage, with polarity, across R$3,$ V$3.(5$ pts$.)$ e$.$ If R$3$ were treated as the load resistor $($the $$blue$$ resistor$)$ in the circuit, what would its resistance need to be in order for it to equal the Thevenin, or Norton, equivalent resistance for the rest of the network?