Math Problem Statement

Complete the square for the given quadratic expressions: (a) x^2 - 2x - 8, (b) x^2 + 4x - 1, (c) x^2 + 10x + 3, (d) x^2 - 16x - 3, (e) x^2 + 18x + 7, (f) x^2 - 32x - 1.

Solution

The exercise focuses on completing the square to rewrite quadratic trinomials in the form (x+b)2+c(x + b)^2 + c. Let’s go through the first example provided, and then we can apply the steps to the exercises in parts (a) through (f).

Example Analysis

The given equation is: x26x8x^2 - 6x - 8

To complete the square:

  1. Take half of the coefficient of xx (which is 6-6), divide by 2 to get 3-3, then square it to get 99.
  2. Add and subtract 99 within the expression: x26x8=(x26x+9)98x^2 - 6x - 8 = (x^2 - 6x + 9) - 9 - 8
  3. This simplifies to: (x3)217(x - 3)^2 - 17

Now, let's apply this method to the exercises:

Solution for Each Part

(a) x22x8x^2 - 2x - 8

  1. Take half of 2-2, square it to get 11.
  2. Rewrite as: x22x8=(x22x+1)18=(x1)29x^2 - 2x - 8 = (x^2 - 2x + 1) - 1 - 8 = (x - 1)^2 - 9

(b) x2+4x1x^2 + 4x - 1

  1. Take half of 44, square it to get 44.
  2. Rewrite as: x2+4x1=(x2+4x+4)41=(x+2)25x^2 + 4x - 1 = (x^2 + 4x + 4) - 4 - 1 = (x + 2)^2 - 5

(c) x2+10x+3x^2 + 10x + 3

  1. Take half of 1010, square it to get 2525.
  2. Rewrite as: x2+10x+3=(x2+10x+25)25+3=(x+5)222x^2 + 10x + 3 = (x^2 + 10x + 25) - 25 + 3 = (x + 5)^2 - 22

(d) x216x3x^2 - 16x - 3

  1. Take half of 16-16, square it to get 6464.
  2. Rewrite as: x216x3=(x216x+64)643=(x8)267x^2 - 16x - 3 = (x^2 - 16x + 64) - 64 - 3 = (x - 8)^2 - 67

(e) x2+18x+7x^2 + 18x + 7

  1. Take half of 1818, square it to get 8181.
  2. Rewrite as: x2+18x+7=(x2+18x+81)81+7=(x+9)274x^2 + 18x + 7 = (x^2 + 18x + 81) - 81 + 7 = (x + 9)^2 - 74

(f) x232x1x^2 - 32x - 1

  1. Take half of 32-32, square it to get 256256.
  2. Rewrite as: x232x1=(x232x+256)2561=(x16)2257x^2 - 32x - 1 = (x^2 - 32x + 256) - 256 - 1 = (x - 16)^2 - 257

Summary

Here are the completed square forms for each part:

  • (a) (x1)29(x - 1)^2 - 9
  • (b) (x+2)25(x + 2)^2 - 5
  • (c) (x+5)222(x + 5)^2 - 22
  • (d) (x8)267(x - 8)^2 - 67
  • (e) (x+9)274(x + 9)^2 - 74
  • (f) (x16)2257(x - 16)^2 - 257

Would you like further explanations on any of these steps?

Follow-up Questions

  1. How can you use the method of completing the square to solve quadratic equations?
  2. Why is completing the square useful for converting a quadratic expression into vertex form?
  3. How does completing the square relate to the formula for the vertex of a parabola?
  4. Can completing the square help in integrating quadratic expressions?
  5. How would the process differ if the coefficient of x2x^2 were not 1?

Tip

When completing the square, remember that you only add and subtract the squared term to form a perfect square, keeping the expression balanced.

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Math Problem Analysis

Mathematical Concepts

Algebra
Completing the Square
Quadratic Expressions

Formulas

(x + b)^2 = x^2 + 2bx + b^2

Theorems

Completing the Square

Suitable Grade Level

Grade 9