2
$\begingroup$

I was reading the solution of a problem and I can't figure out how to go from here:

$k^4 + 2k^3 -k^2 - 2k + 1$

to:

$((k^2 + k) -1)^2$

I guess it's using the complete-the-square method but I've only used that with quadratic expressions.

  • 1
    $k^4 + 2k^3 -k^2 - 2k + 1=k^4 + 2k^3 +k^2 -2k^2 - 2k + 1=k^4 + 2k^3 + k^2 -2(k^2 + k) + 1$...2011-10-16

2 Answers 2