Error Analysis – Describe and correct the error a student made when multiplying two binomials. (2x + 2) (4x –

Question

Error Analysis – Describe and correct the error a student made when multiplying two

binomials.

(2x + 2) (4x – 1)

8x ² – 2

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Doris 4 years 2021-08-15T16:40:41+00:00 1 Answers 7 views 0

Answers ( )

  1. thuhuong
    0
    2021-08-15T16:42:33+00:00
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    Answer:

    The correct answer is:

    Error made: The student multiplied only corresponding terms in each bracket with each other

    Correction: Each term in one bracket is to be multiplied with every term in the next bracket

    Step-by-step explanation:

    The student paired the terms in the brackets into like terms and multiplied the like terms like this:

    (2x + 2) × (4x – 1)  

    collecting like terms: (2x, 4x) (2, -1)

    (2x × 4x) (2 × (-1)) = 8x² – 2.

    The above is the wrong way of expanding the bracket. The correct way of doing it is as follows:

    (2x + 2) (4x – 1)

    Each term in one bracket multiplies each term in the second bracket.

    = 2x (4x – 1) + 2(4x -1)

    = 8x² – 2x + 8x – 2

    = 8x² + 6x – 2

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )