Mathematics

factorise 
2x^2 - x - 1 
help me


Answers

Quan336

4 years ago Comment

ok what i like to do is this...

look at the expression you know that there are 2 x's so you pull these out first keeping in mind that there is a coefficient
(2x   )(x     ) 

now think what 2 numbers gives me "-1" you think "1" and "-1"  (remember that you might have a few different factors)

if you plug those in... (remember that where you place these numbers does matter)
(2x+1)(x-1)

now check using FOIL !!

 

yassautumn

4 years ago Comment

[latex]2x^2 - x - 1 =\\ 2x^2-2x+x-1=\\ 2x(x-1)+1(x-1)=\\ (2x+1)(x-1)[/latex]