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Evaluate Algebraic Expressions and formulas

7.5 lesson

User ITHelpGuy
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1 Answer

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Answer:

1)$97 in 8 weeks. 2) 11 weeks.

  • Addition, Multiplication
  • Follow the acronym PEMDA Power, Multiplication, Division, Addition (Subtraction)

Explanation:

1) Amir is saving money to buy an MP3 player that costs

$120. He starts with $25, and each week he saves $9.

The expression 25 + 9w gives the amount in dollars

that Amir will have saved after w weeks.


25+9w

Set the expression. We don't know yet how much does that worth.

a) How much will Amir have saved after 8 weeks?

Replace 8 for w:


25+9w\\25+9(8)\\25+72\\97

$97 in 8 weeks.

2) After how many weeks will Amir have saved enough money to buy the MP3 player?

Week | Value of 25 + 9w |Amount Saved

9 |25 + 9 × (9) = 25 + 81= 106

10 |25 + 9 × (10) = 25 +90= 115

11 |25 + 9 × 11 = 25 + 99= 124

Answer: After 11 weeks

  • Which operations does the expression 25 + 9w include?

Addition, Multiplication

  • In what order should you perform the operations?

Follow the acronym PEMDA Power, Multiplication, Division, Addition (Subtraction)

User Fedmest
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