This paper aims to clarify how the use of the GeoGebra dynamic geometry program helps students understand the relationships between different representations of a linear function and develop the ability to plot a linear function. The study was based on a quasi-experimental design. In control classes, the topic of functions was presented without using computers for learning. In experimental classes, computers were used in addition to traditional instruction. The control group had 84 and the experimental group 128 students. The results of the study suggest that students' understanding of the linear function and their skills to explain need to be developed in both, the experimental and control groups. Since the experimental group students performed better, the results of this study may encourage teachers to use the dynamic geometry program when teaching linear functions. For productive computer use it is necessary to design tasks that guide students to discover links between different representations of the linear function.