1. The problem states that every variable \(m\) or \(n\) should be replaced by \(x\).\n2. This means wherever you see \(m\) or \(n\) in an expression, equation, or function, substitute \(x\) instead.\n3. For example, if you have an expression like \(m^2 + n\), after substitution it becomes \(x^2 + x\).\n4. This substitution simplifies the problem by unifying the variables into a single variable \(x\), making it easier to analyze or solve.\n5. Always double-check the original expressions to ensure all \(m\) and \(n\) are replaced correctly with \(x\).