Solve this quadratic equation

  • #1

Homework Statement


3x2-8x-1=0


Homework Equations





The Attempt at a Solution


So here i attempt to solve the equation...usually the way i go about this is

you multiply 3 by -1

you get -3

then i ask myself what multiplies to -3 and adds to -8.....after that i am able to solve it...but for some reason i havent been able to come up with a combination of numbers that answer that question and i am stuck...if anyone can tell me what those combination of numbers are...or better yet can solve it for me so i can see how it was done, would be greatly appreciated :)
 

Answers and Replies

  • #2
35,129
6,876

Homework Statement


3x2-8x-1=0


Homework Equations





The Attempt at a Solution


So here i attempt to solve the equation...usually the way i go about this is

you multiply 3 by -1

you get -3

then i ask myself what multiplies to -3 and adds to -8.....after that i am able to solve it...but for some reason i havent been able to come up with a combination of numbers that answer that question and i am stuck...if anyone can tell me what those combination of numbers are...or better yet can solve it for me so i can see how it was done, would be greatly appreciated :)

There are three ways to solve quadratic equations - four if you count guessing, which is almost never a viable approach, and isn't viable for this problem. The three ways are:
1. Factoring the equation
2. Using the Quadratic Formula
3. Completing the square (which is what the Quadratic Formula does for you)

Surely at least one of these techniques has been presented in your class.
 
  • #3
Ray Vickson
Science Advisor
Homework Helper
Dearly Missed
10,706
1,722

Homework Statement


3x2-8x-1=0


Homework Equations





The Attempt at a Solution


So here i attempt to solve the equation...usually the way i go about this is

you multiply 3 by -1

you get -3

then i ask myself what multiplies to -3 and adds to -8.....after that i am able to solve it...but for some reason i havent been able to come up with a combination of numbers that answer that question and i am stuck...if anyone can tell me what those combination of numbers are...or better yet can solve it for me so i can see how it was done, would be greatly appreciated :)

Just use the standard formula for the solution of a quadratic equation. If you don't know it, look in your textbook or search on-line for "quadratic equation".
 

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