You are here:
- Home
- Science
- Mathematics
- Advanced Math
- Solve by completing the square...
Advanced Math/Solve by completing the square...
Advertisement
Question
Solve by completing the square 4x^2 +2x - 1 = 0.
4x^2 + 2x - 1 = 0
add 1 to both sides
4x^2 + 2x = 1
divide everything by 4
x^2 + (1/2)x = (1/4)
find half of (1/2), square it, then add it to both sides
x^2 + (1/2)x + (1/16) = (5/16)
factor the left side into a perfect square
(x + (1/4))^2 = (5/16)
sqrt both sides
x + (1/4) = ħsqrt(5/16)
x + (1/4) = ħ(1/4)sqrt(5)
subtract (1/4) from both sides
x = (-1/4) ħ (1/4)sqrt(5)
so
x = (-1/4) + (1/4)sqrt(5) or (-1/4) - (1/4)sqrt(5)
- Add to this Answer
- Ask a Question
Questioner's Rating
| Rating(1-10) | Knowledgeability = 10 | Clarity of Response = 10 | Politeness = 10 |
| Comment | WOW! Thanks for the explanation. You were a HUGE help! Thanks again! | ||
Related Articles
- Stitch DIY Baby's First Prayerbook Khanda Appliqué - DIY Baby's First Prayerbook With Sikhism Theme
- Make a Patchwork Cat Quilt Block - Free Cat Quilt Block Patterns - Cat Quilts
- Greek Cross Quilt Block Pattern - Make a Greek Cross Quilt - Quilt Patterns
- Using Percents - Website Statistics
- mathematics week one warm ups - questions to begin the school day
Advanced Math
Answers by Expert:
Sherman D.
Expertise
I can answer questions dealing in mathematics of all kinds except for Physics and Calculus, but i can answer questions in Pre-Calculus and Chemistry. I can also answer questions in Recipes of all kinds. I can find games cheats/walkthroughs, but i can`t find a specific game online or offline. I can also do history and recipes for alcoholic beverages.
Experience
Mathematics, Recipes, History, and Games.
Education/Credentials
High School graduated. I graduated with honors, and i was in Beta Club for a year and a half.
Awards and Honors
Principle's list and A and B honor roll in high school only.
©2012 About.com, a part of The New York Times Company. All rights reserved.