The length of a rectangle is four meters less than twice its width.

If the area of the rectangle is 96 m^2, what is the length and the width?

(3 points)
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An expression for the length of the rectangle in terms of the width would be Response area

The formula for the area of a rectangle is Response area

Using trial and error, if the area is 96 m^2, then the length and width are Response area

The option "\(l=8\ \&\ w=12\)" (7 of 10) has been selected. Press tab to choose a response area, and spacebar to insert it. Press escape to cancel.

3 answers

Let's break down the problem step-by-step based on the information provided.

  1. Expression for the length in terms of the width: The problem states that the length (\(l\)) is four meters less than twice its width (\(w\)). Therefore: \[ l = 2w - 4 \]

  2. Formula for the area of a rectangle: The area (\(A\)) of a rectangle is given by the formula: \[ A = l \times w \]

  3. Using the area to set up the equation: We know the area of the rectangle is 96 m², thus: \[ l \times w = 96 \] Substituting the expression for \(l\) from step 1: \[ (2w - 4) \times w = 96 \]

  4. Expanding and rearranging: Expanding the equation gives: \[ 2w^2 - 4w = 96 \] Rearranging it: \[ 2w^2 - 4w - 96 = 0 \] Dividing the entire equation by 2 to simplify: \[ w^2 - 2w - 48 = 0 \]

  5. Factoring the quadratic equation: To factor \(w^2 - 2w - 48 = 0\), we look for two numbers that multiply to -48 and add to -2. The numbers are -8 and 6. Therefore: \[ (w - 8)(w + 6) = 0 \]

  6. Solving for \(w\): Setting each factor equal to zero gives: \[ w - 8 = 0 \quad \Rightarrow \quad w = 8 \] \[ w + 6 = 0 \quad \Rightarrow \quad w = -6 \quad (\text{not valid since width can't be negative}) \]

    Therefore, \(w = 8\) meters.

  7. Finding the corresponding length: Now, substitute \(w = 8\) back into the expression for \(l\): \[ l = 2(8) - 4 = 16 - 4 = 12 \text{ meters} \]

In conclusion:

  • The width is \(8\) meters.
  • The length is \(12\) meters.

You can now fill out the responses accordingly:

  1. Expression for the length of the rectangle in terms of the width: \(l = 2w - 4\)
  2. The formula for the area of a rectangle: \(A = l \times w\)
  3. Using trial and error, if the area is 96 m², then the length and width are: \(l = 12 \text{ m} & w = 8 \text{ m}\)
make the answers more clearer

Certainly! Here are the answers presented more clearly:

  1. Expression for the length of the rectangle in terms of the width: \[ l = 2w - 4 \]

  2. Formula for the area of a rectangle: \[ A = l \times w \]

  3. Using trial and error, if the area is 96 m², then the length and width are: \[ \text{Length } (l) = 12 \text{ meters} \quad \text{and} \quad \text{Width } (w) = 8 \text{ meters} \]

In summary:

  • Width: 8 meters
  • Length: 12 meters