## Calculus with Applications (10th Edition)

$a^{2}-4ab+4b^{2}$
Write out the equation $(a-2b)^{2}$ While you may be tempted to simply square $a$ and $-2b$ this is incorrect. Remember that when an entire expression is squared it is multiply itself by itself when expanding the equation: $(a-2b)(a-2b)$ Multiply each term in the first polynomial by each term in the second polynomial. $a^{2}-2ab-2ab+4b^{2}$ $a^{2}-4ab+4b^{2}$