Chapter 1 - Review - Exercises - Page 134: 27

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

$Factor$ $the$ $expression$ $completely:$ $x^4-2x^2+1$ Factor the trinomial to binomials [Note: the signs is minus then plus, so there must be two negative parenthesis being multiplied together] $x^4-2x^2+1 = (x^2-1)(x^2-1)$ $(x^2-1)(x^2-1)$ = $((x+1)(x-1))\times((x+1)(x-1))$ $((x+1)(x-1))\times((x+1)(x-1))$ = $(x-1)^2(x+1)^2$