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Evaluating expressions is an essential skill in algebra. It involves finding the value of an expression when the variables within it are replaced with specific numbers. This process helps us understand how expressions behave under different conditions.
When evaluating an expression, follow these basic steps:

• Identify the variables in the expression.
• Determine the specific values that the variables will take.
• Replace each variable in the expression with the given number.

After substitution, you'll have an expression that contains only numbers and no variables. From here, you can proceed to simplify and calculate the final value. This step-by-step approach makes the process organized and straightforward.

Substitution in algebra is a technique where you replace variables with specific numbers or other algebraic expressions. This method is often used to solve problems that ask you to find the value of an algebraic expression for specific variable values. Let's walk through this concept using our specific problem.
In the expression \(\frac{2x + 4}{1 + x}\) with \(x = 0\), substitution involves replacing every instance of \(x\) with the number \(0\). This changes the expression into \(\frac{2(0) + 4}{1 + 0}\). Once variables are replaced with numbers, the expression simplifies into a numerical form. Substitution is a vital step before moving on to calculation and simplification because it transforms algebraic expressions into arithmetic problems, which are often easier to manage.

Simplification in algebra is the process of reducing an expression to its simplest form, making it easier to read and work with. It involves basic arithmetic operations such as addition, subtraction, multiplication, and division.
In our exercise, after substitution, we start with simplifying the numerator and denominator separately:

• For the numerator \(2(0) + 4\), multiply \(2\) by \(0\) (which is \(0\)), and add \(4\) to reach \(4\).
• For the denominator \(1 + 0\), simply add \(\(1\)\) and \(\(0\)\) to get \(1\).

Once you have the simplified numerator \(4\) and the denominator \(1\), you can evaluate the fraction \(\frac{4}{1}\), which equals \(4\). Simplification makes the expression as manageable as possible, revealing clearer insights into how changes affect the expression.