Evaluating Expressions by Substitution

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What is an expression in mathematics?

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An expression is a combination of numbers, variables, and operators (such as +, -, *, /) that represents a value.

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What does it mean to evaluate an expression?

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To evaluate an expression means to calculate its value by substituting the variables with given numbers.

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What is substitution in the context of evaluating expressions?

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Substitution is the process of replacing variables in an expression with their corresponding numerical values.

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6

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The first step is to substitute the values of a and b into the expression.

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The simplified form is 3a.

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12

Front

What is the importance of simplifying expressions before evaluating them?

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Simplifying expressions can make calculations easier and reduce the chance of errors.

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What is a variable in an expression?

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A variable is a symbol (usually a letter) that represents an unknown value.

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What is the difference between an expression and an equation?

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An expression does not have an equality sign, while an equation states that two expressions are equal.