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What is the range of this quadratic function?\newliney=x210x+21y = x^2 - 10x + 21\newlineChoices:\newline(A)yy5{y | y \geq 5}\newline(B)yy5{y | y \leq 5}\newline(C)yy4{y | y \geq -4}\newline(D)all real numbers

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Q. What is the range of this quadratic function?\newliney=x210x+21y = x^2 - 10x + 21\newlineChoices:\newline(A)yy5{y | y \geq 5}\newline(B)yy5{y | y \leq 5}\newline(C)yy4{y | y \geq -4}\newline(D)all real numbers
  1. Identify Quadratic Function: Identify the quadratic function.\newlineWe are given the quadratic function y=x210x+21y = x^2 - 10x + 21.
  2. Find Vertex: Find the xx-coordinate of the vertex.\newlineTo find the vertex of the parabola, we use the formula x=b2ax = -\frac{b}{2a}, where aa is the coefficient of x2x^2 and bb is the coefficient of xx. In this case, a=1a = 1 and b=10b = -10.\newlinex=1021x = -\frac{-10}{2 \cdot 1}\newlinex=102x = \frac{10}{2}\newlinex=b2ax = -\frac{b}{2a}00
  3. Find Y-Coordinate: Find the y-coordinate of the vertex.\newlineSubstitute x=5x = 5 into the quadratic function to find the y-coordinate of the vertex.\newliney=(5)210(5)+21y = (5)^2 - 10(5) + 21\newliney=2550+21y = 25 - 50 + 21\newliney=25+21y = -25 + 21\newliney=4y = -4
  4. Determine Parabola Direction: Determine the direction of the parabola. Since the coefficient of x2x^2 (a=1a = 1) is positive, the parabola opens upwards.
  5. Find Range: Find the range of the function.\newlineThe vertex of the parabola is (5,4)(5, -4), and since the parabola opens upwards, the yy-values will be greater than or equal to the yy-coordinate of the vertex.\newlineRange: \{yy4y | y \geq -4\}
  6. Match Range with Choices: Match the range with the given choices.\newlineThe correct range is not listed in the choices provided. There seems to be an error in the choices, as none of them match the calculated range of yy4{y | y \geq -4}.

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