知识点 1
Represent a context with equations, inequalities, functions, or diagrams.
Match each part of the context to the right mathematical form: variable, fixed amount, rate, or restriction.
核心知识
Build the model by matching each part of the context to a mathematical role: variable, fixed amount, repeated rate, or restriction.
深入理解
Rule: Match the math form to the story.
- A one-time fee becomes a constant term.
- A per phrase usually becomes a coefficient.
- A limit like "at most" or "no fewer than" should become an inequality.
- A diagram can help when the context is geometric or visual.
分步讲解
- Choose a variable and state what it measures.
- Mark which quantity is fixed and which quantity changes.
- Translate rates, totals, and limits one piece at a time.
- Read the finished model back in words to check that it matches the situation.
常见误解
- Reversing the fixed amount and the rate, such as writing the fee as the coefficient of the variable.
- Using an equation when the context gives a maximum or minimum and should be modeled with an inequality.
- Ignoring the units, which can hide whether a number belongs in the rate or in the constant term.
题目
示例解析
A theater charges a one-time online order fee of $6 plus $14 for each ticket. Which function gives the total cost
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