6

Set 8: Quadratic Equations (Intermediate)

Explanation

Answer: A

The area of a rectangular garden is given by A=x2+5x+6A = x^2 + 5x + 6. If the width is (x+2)(x + 2), what is the length?

A.

(x+3)(x + 3)

✓ Correct
B.

(x+4)(x + 4)

C.

(x+2)(x + 2)

D.

(x+1)(x + 1)

Detailed Explanation

Choice A is correct. Choice A is the correct answer. The area of a rectangle is Area=Length×Width\text{Area} = \text{Length} \times \text{Width}. 1. We are given Area =x2+5x+6= x^2 + 5 x + 6 and Width =(x+2)= (x + 2). 2. We need to find the other factor of the quadratic. 3. Factor x2+5x+6x^2 + 5 x + 6: We need numbers that multiply to 6 and add to 5. They are 2 and 3. 4. So, x2+5x+6=(x+2)(x+3)x^2 + 5 x + 6 = (x + 2)(x + 3). Since the width is (x+2)(x + 2), the length must be (x+3)(x + 3). Choice B is incorrect because (x+2)(x+4)=x2+6x+8(x+2)(x+4) = x^2 + 6 x + 8. Choice C is incorrect because (x+2)(x+2)=x2+4x+4(x+2)(x+2) = x^2 + 4 x + 4. Choice D is incorrect because (x+2)(x+1)=x2+3x+2(x+2)(x+1) = x^2 + 3 x + 2.

Key Steps:

The correct answer is (x+3)(x + 3)

Why others are wrong:
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.

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