1. Let's identify the context first: the expression was simplified to 2x in step 4. 2. Usually, this comes from combining like terms or simplifying a multiplication or division. 3. For example, if you have something like $x + x$, it simplifies to $2x$ because you add the coefficients (1 + 1 = 2) and keep the variable the same. 4. Another common case is factoring: if you have $2 \times x$, it simply becomes $2x$. 5. Without the exact original expression from step 4, the general rule is: coefficients multiply or add, and the variable remains. 6. So in your case, the term reduced to $2x$ because the numbers combined to 2, and the $x$ stayed unchanged. 7. If you provide the exact step 3 and 4 expressions, I can explain precisely.