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y=x^(2)+4x-21
The given equation represents a parabola in the 
xy-plane. Which of the following equivalent forms of the equation displays the 
x intercepts of the parabola as constants or coefficients?
Choose 1 answer:
(A) 
y=(x-3)(x+7)
(B) 
y=x(x+4)-21
(c) 
y=(x+2)^(2)-25
(D) 
y+24=(x+1)(x+3)

y=x2+4x21 y=x^{2}+4 x-21 \newlineThe given equation represents a parabola in the xy x y -plane. Which of the following equivalent forms of the equation displays the x x intercepts of the parabola as constants or coefficients?\newlineChoose 11 answer:\newline(A) y=(x3)(x+7) y=(x-3)(x+7) \newline(B) y=x(x+4)21 y=x(x+4)-21 \newline(C) y=(x+2)225 y=(x+2)^{2}-25 \newline(D) y+24=(x+1)(x+3) y+24=(x+1)(x+3)

Full solution

Q. y=x2+4x21 y=x^{2}+4 x-21 \newlineThe given equation represents a parabola in the xy x y -plane. Which of the following equivalent forms of the equation displays the x x intercepts of the parabola as constants or coefficients?\newlineChoose 11 answer:\newline(A) y=(x3)(x+7) y=(x-3)(x+7) \newline(B) y=x(x+4)21 y=x(x+4)-21 \newline(C) y=(x+2)225 y=(x+2)^{2}-25 \newline(D) y+24=(x+1)(x+3) y+24=(x+1)(x+3)
  1. Factor Quadratic Equation: To find the xx-intercepts of the parabola, we need to factor the quadratic equation if possible. The given equation is y=x2+4x21y = x^2 + 4x - 21. We will look for two numbers that multiply to 21-21 and add up to 44.
  2. Identify Correct Factored Form: The two numbers that satisfy these conditions are 77 and 3-3 because 7×(3)=217 \times (-3) = -21 and 7+(3)=47 + (-3) = 4. Therefore, we can factor the quadratic equation as y=(x3)(x+7)y = (x - 3)(x + 7).
  3. Confirm Matching Choice (A): Now we will check the answer choices to see which one matches the factored form of the equation. The factored form should directly show the xx-intercepts as constants or coefficients.
  4. Review Other Choices: Choice (A) y=(x3)(x+7)y = (x - 3)(x + 7) matches the factored form we found, which displays the xx-intercepts of the parabola as constants or coefficients. The xx-intercepts are x=3x = 3 and x=7x = -7.
  5. Choice (B) Analysis: We will quickly review the other choices to confirm that they do not display the xx-intercepts in the same clear manner as choice (A).
  6. Choice (C) Analysis: Choice (B) y=x(x+4)21y = x(x + 4) - 21 does not display the xx-intercepts as constants or coefficients in a factored form.
  7. Choice (D) Analysis: Choice (C) y=(x+2)225y = (x + 2)^2 - 25 is in vertex form and does not display the xx-intercepts as constants or coefficients.
  8. Choice (D) Analysis: Choice (C) y=(x+2)225y = (x + 2)^2 - 25 is in vertex form and does not display the xx-intercepts as constants or coefficients.Choice (D) y+24=(x+1)(x+3)y + 24 = (x + 1)(x + 3) is not in the standard form of a quadratic equation and does not display the xx-intercepts as constants or coefficients.

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