Topic: Mathematical Reasoning

A student solves 3(x + 4) as 3x + 4. What is the mistake?

• The 3 was not multiplied by 4
• The x should be divided by 3

A student says x^2 + x^3 = x^5. What is the mistake?

• The answer should be x^6
• Unlike powers were added as if multiplying
• The bases are different

A student solves -2x < 8 and writes x < -4. What is the mistake?

• The inequality sign was not reversed
• x should be positive
• There is no mistake
• 8 should be divided by 2 only

A student solves 3(x + 4) as 3x + 4. What is the mistake?

• The 3 was not multiplied by 4
• The plus sign should become minus
• The x should be divided by 3

A student says x^2 + x^3 = x^5. What is the mistake?

• The bases are different
• Unlike powers were added as if multiplying

A student solves 3(x + 4) as 3x + 4. What is the mistake?

• The x should be divided by 3
• The 3 was not multiplied by 4
• The plus sign should become minus
• There is no mistake

A student solves 3(x + 4) as 3x + 4. What is the mistake?

• The 3 was not multiplied by 4
• The x should be divided by 3
• The plus sign should become minus

A student says x^2 + x^3 = x^5. What is the mistake?

• There is no mistake
• The bases are different
• Unlike powers were added as if multiplying
• The answer should be x^6

A student solves 3(x + 4) as 3x + 4. What is the mistake?

• The plus sign should become minus
• The 3 was not multiplied by 4
• There is no mistake
• The x should be divided by 3

A student solves 3(x + 4) as 3x + 4. What is the mistake?

• The x should be divided by 3
• There is no mistake
• The 3 was not multiplied by 4
• The plus sign should become minus