A series AC circuit has a resistance of 6 ohms, an inductive reactance of 10 ohms, and a capacitive reactance of 2 ohms. What is the impedance of the circuit?

Why B is correct

Net reactance X = XL − XC = 10 − 2 = 8 Ω. Impedance Z = √(R² + X²) = √(36 + 64) = √100 = 10 Ω. Simply summing all three values arithmetically gives 18 Ω, which ignores the vector relationship between resistance and reactance. (NEETS Mod. 2 §4-1)