Math Problem Statement

Consider the parabola given by the equation f(x) = 2x^2 + 14x - 2. Find the vertex, axis of symmetry, y-intercept, and zeros of the parabola.

Solution

To solve this problem, let’s break down each part of the function f(x)=2x2+14x2f(x) = 2x^2 + 14x - 2.

Step-by-Step Solution

A) The Vertex

The vertex of a parabola f(x)=ax2+bx+cf(x) = ax^2 + bx + c can be found using the formula: x=b2ax = -\frac{b}{2a} where a=2a = 2 and b=14b = 14.

  1. Calculate the xx-coordinate of the vertex: x=142×2=144=3.5x = -\frac{14}{2 \times 2} = -\frac{14}{4} = -3.5

  2. Substitute x=3.5x = -3.5 back into the function to find the yy-coordinate: f(3.5)=2(3.5)2+14(3.5)2f(-3.5) = 2(-3.5)^2 + 14(-3.5) - 2 =2(12.25)492=24.5492=26.5= 2(12.25) - 49 - 2 = 24.5 - 49 - 2 = -26.5

So, the vertex is: Vertex=(3.5,26.5)\text{Vertex} = (-3.5, -26.5)

B) The Axis of Symmetry

The axis of symmetry is the vertical line that passes through the xx-coordinate of the vertex. Therefore: Axis of Symmetry=x=3.5\text{Axis of Symmetry} = x = -3.5

C) The Y-Intercept

The yy-intercept occurs when x=0x = 0: f(0)=2(0)2+14(0)2=2f(0) = 2(0)^2 + 14(0) - 2 = -2 So, the yy-intercept is: Y-intercept=(0,2)\text{Y-intercept} = (0, -2)

D) The Zeros of the Parabola (x-intercepts)

To find the zeros of the function, set f(x)=0f(x) = 0: 2x2+14x2=02x^2 + 14x - 2 = 0

This is a quadratic equation in standard form ax2+bx+c=0ax^2 + bx + c = 0, which we can solve using the quadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

  1. Substitute a=2a = 2, b=14b = 14, and c=2c = -2: x=14±14242(2)22x = \frac{-14 \pm \sqrt{14^2 - 4 \cdot 2 \cdot (-2)}}{2 \cdot 2} =14±196+164= \frac{-14 \pm \sqrt{196 + 16}}{4} =14±2124= \frac{-14 \pm \sqrt{212}}{4} =14±14.564= \frac{-14 \pm 14.56}{4}

  2. Calculate each solution:

    • For the ++ case: x=14+14.564=0.564=0.14x = \frac{-14 + 14.56}{4} = \frac{0.56}{4} = 0.14
    • For the - case: x=1414.564=28.564=7.14x = \frac{-14 - 14.56}{4} = \frac{-28.56}{4} = -7.14

So, the zeros are: Zeros=(0.14,0),(7.14,0)\text{Zeros} = (0.14, 0), (-7.14, 0)

Summary of Answers

  • A) The vertex is (3.5,26.5)(-3.5, -26.5).
  • B) The axis of symmetry is x=3.5x = -3.5.
  • C) The yy-intercept is (0,2)(0, -2).
  • D) The zeros are (0.14,0)(0.14, 0) and (7.14,0)(-7.14, 0).

Would you like further explanation on any part of this solution?


Here are some related questions to deepen understanding:

  1. How would the vertex change if the aa-value in the equation were negative?
  2. What does the yy-intercept represent in the context of this parabola?
  3. How do the zeros of the parabola relate to its graph on the coordinate plane?
  4. What role does the axis of symmetry play in determining the shape of the parabola?
  5. How can the quadratic formula be applied to other types of functions?

Tip: Always double-check calculations when using the quadratic formula, especially under the square root, to avoid common errors.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Parabolas

Formulas

Vertex formula for parabolas
Axis of symmetry formula
Quadratic formula for zeros

Theorems

Quadratic formula

Suitable Grade Level

Grades 9-10