Using the Superposition Theorem: (a) Determine the magnitude and direction of the current in resistor R4. (b) Find the magnitude and orientation of the voltage across R5. R₁ 2.2 kn 7.5 k ww R₁ 9.1 k E₁18 V R& Rs 6.8 k + E3V R₂ 3.3 k