Jason made his first mistake in Step 2.
The correct factoring of the quadratic equation \(x^2 - 4x - 12 = 0\) is \((x - 6)(x + 2) = 0\). However, the correct solutions from those factors should be \(x - 6 = 0\) leading to \(x = 6\) and \(x + 2 = 0\) leading to \(x = -2\), not \(x = 2\).
So, the error occurs at Step 2 where he incorrectly stated the factored form's solutions. Therefore, the first mistake is in Step 2.