Chapter 9 - Solving Quadratic Equations - 9.4 - Solving Quadratic Equations by Completing the Square - Monitoring Progress - Page 506: 2

$=x^2-4x+4$ $=(x-2)^2$

The given expression is $=x^2-4x$ Find the value of $(\frac{b}{2})^2$. Substitute $-4$ for $b$. $=(\frac{-4}{2})^2$ Simplify. $=(-2)^2$ $=4$ Add $4$ to the given expression. $=x^2-4x+4$ Write the the polynomial as $a^2+2ab+b^2$. $=x^2-2(x)(2)+2^2$ Use perfect square trinomial pattern $a^2-2ab+b^2=(a-b)^2$ We have $a=x$ and $b=2$. $=(x-2)^2$