Math Problem Statement

Write the equation y = x^2 - 2x - 1 in vertex form.

Solution

The problem states the quadratic equation y=x22x1y = x^2 - 2x - 1, and asks to write it in vertex form.

Vertex Form of a Quadratic Equation:

The vertex form is written as: y=a(xh)2+ky = a(x-h)^2 + k where (h,k)(h, k) is the vertex of the parabola.

To convert y=x22x1y = x^2 - 2x - 1 into vertex form, we use completing the square:


Step 1: Group the quadratic and linear terms

y=(x22x)1y = (x^2 - 2x) - 1


Step 2: Complete the square

Take half the coefficient of xx, square it, and add/subtract it inside the parentheses.

The coefficient of xx is 2-2. Half of 2-2 is 1-1, and squaring it gives: (1)2=1(-1)^2 = 1

Now add and subtract 11 inside the parentheses: y=(x22x+11)1y = (x^2 - 2x + 1 - 1) - 1

y=((x1)21)1y = ((x - 1)^2 - 1) - 1


Step 3: Simplify

y=(x1)22y = (x - 1)^2 - 2


Final Answer:

The equation in vertex form is: y=(x1)22y = (x - 1)^2 - 2

The vertex is at (1,2)(1, -2).


Would you like further clarifications or additional examples?

Related Questions:

  1. How do you find the vertex of a parabola given in standard form?
  2. What is the axis of symmetry of the parabola y=(x1)22y = (x - 1)^2 - 2?
  3. How does completing the square relate to factoring quadratics?
  4. What are some practical applications of the vertex form of a quadratic equation?
  5. How do you graph a parabola given in vertex form?

Tip:

When completing the square, always check your work by expanding the vertex form back into standard form to ensure correctness!

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Vertex Form
Completing the Square

Formulas

Vertex form of a quadratic equation: y = a(x - h)^2 + k
Completing the square: (b/2)^2

Theorems

Parabola Vertex Theorem

Suitable Grade Level

Grades 8-10