If y=−21x2−9 is graphed in the xy-plane, which of the following characteristics of the graph are displayed as a constant or coefficient in the equation?I. x-intercept(s)II. y-interceptIII. y-coordinate of the vertexChoose 1 answer:(A) II only(B) III only(C) I and II only(D) II and III only
Q. If y=−21x2−9 is graphed in the xy-plane, which of the following characteristics of the graph are displayed as a constant or coefficient in the equation?I. x-intercept(s)II. y-interceptIII. y-coordinate of the vertexChoose 1 answer:(A) II only(B) III only(C) I and II only(D) II and III only
Recognize Standard Form: The given quadratic equation is y=−(21)x2−9. To understand which characteristics of the graph are displayed as a constant or coefficient in the equation, we first need to recognize the standard form of a quadratic equation, which is y=ax2+bx+c, where:- a is the coefficient that determines the direction and "width" of the parabola,- b is the coefficient related to the symmetry of the parabola and the x-coordinate of the vertex,- c is the constant term that gives the y-intercept of the graph.In our equation, a=−(21), b=0, and c=−9.
Coefficient a Analysis: The coefficient a=−(21) determines the direction (since it's negative, the parabola opens downwards) and the "width" of the parabola but does not directly give us the x-intercepts or the y-coordinate of the vertex. It does influence the shape and direction of the parabola.
Coefficient b Analysis: Since b=0 in our equation, there is no term that directly affects the x-coordinate of the vertex in the form of bx. This means that the vertex's x-coordinate is not directly given by the equation in its current form. However, the absence of b indicates symmetry about the y-axis.
Constant Term c Analysis: The constant term c=−9 is the y-intercept of the graph. This is because when x=0, y=c. Therefore, the point (0,−9) is where the graph intersects the y-axis.
Vertex Calculation: The y-coordinate of the vertex in a quadratic equation in the form y=ax2+bx+c can be found using the formula −2ab for the x-coordinate of the vertex and then substituting this back into the equation to find the y-coordinate. However, since b=0 in our equation, the x-coordinate of the vertex is 0, and substituting x=0 into the equation gives us the y-coordinate of the vertex, which is y=ax2+bx+c0. Therefore, the y-coordinate of the vertex is directly given by the constant term in the equation.
Characteristics Summary: Based on the analysis:- The x-intercepts are not directly given by the coefficients or constants in the equation.- The y-intercept is directly given by the constant term c=−9.- The y-coordinate of the vertex is also directly given by the constant term c=−9, as shown in the previous step.Therefore, the characteristics of the graph displayed as a constant or coefficient in the equation are the y-intercept and the y-coordinate of the vertex.
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