Let x = number of games played. Equation:  37.50 – .5x = 42.75 – .75x Step 1:   37.50 – 1.25x = 42.75 Step 2:   – 1.25x = 5.25 Step 3:   – 4.2 = x Sandor knows his answer is incorrect because a negative number of games cannot be played. What was Sandor’s mistake?