Deyj D.

asked • 07/13/15

How would I factor this

2x2-7x-1=0

2 Answers By Expert Tutors

By:

Michael J. answered • 07/14/15

Tutor
5 (5)

Effective High School STEM Tutor & CUNY Math Peer Leader

See tutors like this
See tutors like this
Mike is right about not being factorable.  Although the first and last terms in FOIL are satisfied, the middle term is not.  However, this does not mean there is no solution.  If we use the quadratic formula, we will have two solutions.
 
x = (-b ± √(b2 - 4ac)) / 2a
 
where:
a = 2
b = -7
c = -1
 
 
Plug in these numbers into the formula and you will have your two solutions.
 
 
Upvote • 0 Downvote
More
Report

David W.

This may be a matter of definition/usage of the term factor --
    Aren't   (7 + SQRT(57)) / 2   and (7 - SQRT(57) / 2  "factors?"
 
I'm thinking that:    [(7 + SQRT(57)) / 2] * [(7 - SQRT(57)) / 2] = 0
     Doesn't that make them "factors?  
         (factor, in mathematics = a number or algebraic expression that divides another number or expression evenly) and SQRT(57) is precisely 7.54983443527075000000000000000.
Report

07/14/15

David W.

Corrected comment  [ '(' added]:
 
This may be a matter of definition/usage of the term factor --
    Aren't   (7 + SQRT(57)) / 2   and (7 - SQRT(57)) / 2  "factors?"
 
I'm thinking that:    [(7 + SQRT(57)) / 2] * [(7 - SQRT(57)) / 2] = 0
     Doesn't that make them "factors?  
         (factor, in mathematics = a number or algebraic expression that divides another number or expression evenly) and SQRT(57) is precisely 7.54983443527075000000000000000.
Report

07/14/15

David W.

No, the correction should be a ")"    [note: WyzAnt is aware that we cannot edit comments and that editing Answers is flawed because the dialog box does not display the most recent edited version of our Answer]
 
This may be a matter of definition/usage of the term factor --
    Aren't   (7 + SQRT(57)) / 2   and (7 - SQRT(57)) / 2  "factors?"
 
I'm thinking that:    [(7 + SQRT(57)) / 2] * [(7 - SQRT(57)) / 2] = 0
     Doesn't that make them "factors?  
         (factor, in mathematics = a number or algebraic expression that divides another number or expression evenly) and SQRT(57) is precisely 7.54983443527075000000000000000.

Report

07/14/15

Still looking for help? Get the right answer, fast.

Ask a question for free

Get a free answer to a quick problem.
Most questions answered within 4 hours.

OR

Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.