  We investigate the influence of electrical charge noise on a resonant
exchange (RX) qubit in a triple quantum dot. This RX qubit is a variation of
the exchange-only spin qubit which responds to a narrow-band resonant
frequency. Our noise model includes uncorrelated charge noise in each quantum
dot giving rise to two independent (noisy) bias parameters $\varepsilon$ and
$\Delta$. We calculate the energy splitting of the two qubit states as a
function of these two bias detuning parameters to find "sweet spots", where the
qubit is least susceptible to noise. Our investigation shows that such sweet
spots exist within the low bias regime, in which the bias detuning parameters
have the same magnitude as the hopping parameters. The location of the sweet
spots in the $(\varepsilon,\Delta)$ plane depends on the hopping strength and
asymmetry between the quantum dots. In the regime of weak charge noise, we
identify a new favorable operating regime for the RX qubit based on these sweet
spots.
