Tommy was trying to solve the system of a linear equation and a quadratic equation shown below. 2x – y = –1 x2 – 5x – y = –7 Tommy had completed the following steps in his algebraic solution process but could not factor the resulting quadratic, x2 – 7x – 1, to complete the problem. Step I: y = 2x + 1 Step II: x2 – 5x – (2x + 1) = –7 Step III: x2 – 5x – 2x – 1 = –7 Step IV: x2 – 7x – 1 = –7 Determine the step in which Tommy made his mistake and justify your reasoning.