The Davidson family wants to expand its rectangular patio, which currently measures 15 ft by 12 ft. They want to extend the length and width the same amount to increase the total area of the patio by 160 ft². Which quadratic equation best models the situation?

A. [tex]\((15)(12) + (x)(x) = (15)(12) + 160\)[/tex]
B. [tex]\((15x)(12x) = (15)(12) + 160\)[/tex]
C. [tex]\(2(15+x) + 2(12+x) = (15)(12) + 160\)[/tex]
D. [tex]\((15+x)(12+x) = (15)(12) + 160\)[/tex]



Answer :

To find the quadratic equation that models the situation, let's break down the process step by step.

### Step-by-Step Solution:

1. Current Dimensions:
- The current length of the patio [tex]\( l \)[/tex] is 15 feet.
- The current width of the patio [tex]\( w \)[/tex] is 12 feet.

2. Initial Area Calculation:
- The initial area [tex]\( A \)[/tex] of the patio is calculated as:
[tex]\[ A = l \times w = 15 \times 12 = 180 \text{ square feet} \][/tex]

3. Area Increase:
- The patio's area is to be increased by 160 square feet.
- Therefore, the new total area after expansion will be:
[tex]\[ A_{\text{new}} = 180 + 160 = 340 \text{ square feet} \][/tex]

4. Introducing the Extension:
- Let [tex]\( x \)[/tex] be the length by which both the length and the width are extended.
- The new dimensions will be:
[tex]\[ \text{New Length} = 15 + x \][/tex]
[tex]\[ \text{New Width} = 12 + x \][/tex]

5. Form the Equation:
- The new area should be equal to the total area. So we set up the following equation:
[tex]\[ (15 + x)(12 + x) = 340 \][/tex]

6. Expanding the Equation:
- Expand the left side:
[tex]\[ 15 \cdot 12 + 15 \cdot x + 12 \cdot x + x^2 = 340 \][/tex]
- Simplify the expression:
[tex]\[ 180 + 15x + 12x + x^2 = 340 \][/tex]
- Combine the like terms:
[tex]\[ x^2 + 27x + 180 = 340 \][/tex]

7. Form the Quadratic Equation:
The equation is now in a standard quadratic form [tex]\( ax^2 + bx + c = 0 \)[/tex]:
[tex]\[ x^2 + 27x + 180 - 340 = 0 \][/tex]

8. Final Simplification:
- Simplify the constants:
[tex]\[ x^2 + 27x - 160 = 0 \][/tex]

### Conclusion:
The quadratic equation that best models the situation is:
[tex]\[ (x + 15)(x + 12) = 340 \][/tex]

Which simplifies to:
[tex]\[ x^2 + 27x - 160 = 0 \][/tex]

From the options provided, the correct quadratic equation is:
[tex]\[ \boxed{(15 + x)(12 + x) = (15 \times 12) + 160} \][/tex]

This corresponds to the step-by-step explanation and the equation [tex]\( x^2 + 27x - 160 = 0 \)[/tex].

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