## Intermediate Algebra (6th Edition)

$16(x^{4}+2x^{3}-x^{2}-2x+1)$
$(4x^{2}+4x-4)^{2}$ $=[4(x^{2}+x-1)]^{2}$ $=4^{2}(x^{2}+x-1)^{2}$ $=16(x^{2}+x-1)^{2}$ $=16(x^{2}+(x-1))^{2}$ Using the formula $(a+b)^{2}= a^{2}+2ab+b^{2}$ Let $a$ be $x^{2}$ and $b$ be $(x-1)$ $(x^{2})^{2}+2(x^{2})(x-1)+(x-1)^{2}$ $=16[x^{4}+2x^{2}(x-1)+(x-1)^{2}]$ [Using $(a-b)^{2}= a^{2}-2ab+b^{2}$ $(x-1)^{2}= x^{2}-2x+1$] $=16[x^{4}+2x^{3}-2x^{2}+x^{2}-2x+1]$ Combine like terms. $= 16[x^{4}+2x^{3}-x^{2}-2x+1]$