Open Up - Grade 7 - Mathematics - Unit 6 - Lesson 21

By Formative Library
Last updated about 3 years ago
8 Questions

  • Noah says that9x - 2x + 4x is equivalent to 3x , because the subtraction sign tells us to subtract everything that comes after 9x.
  • Elena says that 9x - 2x + 4x is equivalent to 11x, because the subtraction only applies to 2x .
Do you agree with either of them?

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Identify the error in generating an expression equivalent to 4 + 2x - \frac{1}{2}(10 - 4x). Then correct the error.
4 + 2x + \frac{-1}{2}(10 - 4x).
4 + 2x -5 + 2x.
-1

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Select all expressions that are equivalent to 5x - 15 - 20x +10.

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The school marching band has a budget of up to $750 to cover 15 new uniforms and competition fees that total $300. How much can they spend for one uniform?

Write an inequality to represent this situation.

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The school marching band has a budget of up to $750 to cover 15 new uniforms and competition fees that total $300. How much can they spend for one uniform?

Solve the inequality and describe what it means in the situation.

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Solve the inequality that represents each story.

For every $9 that Elena earns, she gives x dollars to charity. This happens 7 times this month. Elena wants to be sure she keeps at least $42 from this month’s earnings.

7(9 - x)\ge 42

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Solve the inequality that represents each story.

Lin buys a candle that is 9 inches tall and burns down x inches per minute. She wants to let the candle burn for 7 minutes until it is less than 6 inches tall.

9 - 7x < 6

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A certain shade of blue paint is made by mixing 1\frac{1}{2} quarts of blue paint with 5 quarts of white paint. If you need a total of 16.25 gallons of this shade of blue paint, how much of each color should you mix?

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