Math Problem Statement

Identify the axis of symmetry, vertex, y-intercept, and range for the quadratic function.

y = -x2 + 8x - 10 

Solution

Let's analyze the quadratic function:

y=x2+8x10y = -x^2 + 8x - 10

1. Axis of Symmetry

The general form of a quadratic function is:

y=ax2+bx+cy = ax^2 + bx + c

For the axis of symmetry, we use the formula:

x=b2ax = -\frac{b}{2a}

Here, a=1a = -1, b=8b = 8, and c=10c = -10. Substituting into the formula:

x=82(1)=82=4x = -\frac{8}{2(-1)} = \frac{8}{2} = 4

So, the axis of symmetry is x=4x = 4.

2. Vertex

The vertex lies on the axis of symmetry, and its xx-coordinate is 44. To find the yy-coordinate, substitute x=4x = 4 into the original equation:

y=(4)2+8(4)10y = -(4)^2 + 8(4) - 10 y=16+3210=6y = -16 + 32 - 10 = 6

Thus, the vertex is (4,6)(4, 6).

3. Y-Intercept

The yy-intercept occurs when x=0x = 0. Substituting x=0x = 0 into the equation:

y=(0)2+8(0)10=10y = -(0)^2 + 8(0) - 10 = -10

So, the y-intercept is (0,10)(0, -10).

4. Range

Since the coefficient of x2x^2 is negative (a=1a = -1), the parabola opens downwards. The vertex represents the maximum point. The yy-coordinate of the vertex is 6, so the range is:

y6y \leq 6

Thus, the range is (,6](-\infty, 6].

Summary:

  • Axis of symmetry: x=4x = 4
  • Vertex: (4,6)(4, 6)
  • Y-intercept: (0,10)(0, -10)
  • Range: y6y \leq 6 or (,6](-\infty, 6]

Would you like more details or have any questions?

Here are 5 related questions to consider:

  1. How do you find the x-intercepts of a quadratic function?
  2. How does the sign of the coefficient aa affect the direction of the parabola?
  3. What is the significance of the discriminant in a quadratic function?
  4. Can the axis of symmetry ever be negative?
  5. How does changing the constant cc affect the graph of a quadratic function?

Tip: The vertex form of a quadratic function can make it easier to identify the vertex directly!

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Axis of Symmetry
Vertex
Y-intercept
Range

Formulas

Axis of Symmetry: x = -b / 2a
Quadratic Equation: y = ax^2 + bx + c

Theorems

Vertex Theorem
Symmetry in Quadratics

Suitable Grade Level

Grades 9-10