Since slope is calculated using the formula m = startfraction v 2 minus v 1 over x 2 minus x 1 endfraction, the slope of both lines is equivalent to it is given that the lines are parallel, and we calculated that the slopes are the same. therefore, parallel lines have the same slopes. startfraction v minus z over w minus x endfraction startfraction w minus x over v minus z endfraction startfraction v minus z + b over x minus z + a endfraction startfraction w minus x + a over v minus z + b endfraction