8.7 · Part II
Second Practice Form · Independent Application and Spiral Review
Equations and Inequalities Problem Solving · Model
- Define the variable and units in the scenario
- Look for keywords: 'equals/is' (=) vs 'at least/limit' (≥, ≤, >, <)
- Write the algebraic model, solve with inverse operations, and check in context
- Equations and Inequalities Problem Solving (Resolución de problemas con ecuaciones y desigualdades) — Use an equation for one exact value or an inequality for a range of values in a real situation.
- Model (Modelar) — To show a real-life situation with an equation or inequality.
- Equation (Ecuación) — A math sentence with an equal sign showing both sides are the same.
- Inequality (Desigualdad) — A math sentence that compares two sides with <, >, ≤, or ≥.
- Reasonableness (Razonabilidad) — Checking if your answer makes sense.
- Variable (Variable) — A letter that stands for a number that is unknown or can change.
- A common mistake in Equations and Inequalities Problem Solving is matching the wrong model to a key phrase. For 'the getaway car held no more than 6 bags,' students often write the equation b = 6 instead of the inequality b ≤ 6, because they see one number and assume it must be exact. The same mistake happens in reverse: for 'the reward split equally among 5 people gave each $40,' students sometimes write the inequality 5p ≥ 40 instead of the equation 5p = 40, because 'split equally' sounds like it could mean a range. Before you submit, ask: does this phrase give one exact value (equation, =) or a limit/range (inequality, <, >, ≤, ≥)?
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1 MULTIPLE CHOICE
Which model is correct for: 'A number divided by 6 equals 7'?
- An / 6 = 7
- B6n = 7
- Cn − 6 = 7
- Dn + 6 = 7
✏️ Workspace & Solution Steps
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2 MULTIPLE CHOICE
(Lesson 8.5) Which graph represents x < 5?
- AOpen circle at 5, shaded left
- BClosed circle at 5, shaded left
- COpen circle at 5, shaded right
- DClosed circle at 5, shaded right
✏️ Workspace & Solution Steps -
3 MULTIPLE CHOICE
(Lesson 8.5) Which graph represents x ≥ 3?
- AClosed circle at 3, shaded right
- BOpen circle at 3, shaded right
- CClosed circle at 3, shaded left
- DOpen circle at 3, shaded left
✏️ Workspace & Solution Steps -
4 MULTIPLE CHOICE
Room 4: A locked drawer clue reads, 'Five identical evidence boxes weigh 60 pounds in all.' Solve 5w = 60 for each box's weight w.
- Aw = 12
- Bw = 55
- Cw = 300
- Dw = 65
✏️ Workspace & Solution Steps -
5 MULTIPLE CHOICE
A museum has some paintings. After adding 12, they have 45. Which equation models this?
- Ap + 12 = 45
- Bp − 12 = 45
- C12p = 45
- Dp / 12 = 45
✏️ Workspace & Solution Steps -
6 MULTIPLE CHOICE
A detective needs more than 8 hours to finish the investigation. She has already worked 3 hours. Which inequality represents the additional hours h she needs?
- A3 + h > 8
- B3 + h = 8
- Ch > 3
- D8 + h > 3
✏️ Workspace & Solution Steps
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7 OPEN RESPONSE
Create two word problems about the same situation: one that requires an equation and one that requires an inequality. Solve both and explain why the models are different.
✏️ Mathematical Justification & Response
Writing Task: Justify why your mathematical solution is accurate and complete.