Among the natural phenomena that happen in the Sun, one that has direct impact on Earth are the solar explosions. These explosions emit an X-ray flux that can be detected and used as an indicative of new explosions. In this work, we evaluated whether X-ray flux time series are suitable as the base dataset for solar flare forecasting. To do so, we applied a multilayer perceptron (MLP) neural network. The experiments indicated that X-ray flux time series can be used to forecast solar flares, even though the average errors increase with wider forecast horizons.