body{margin:0;} noscript{z-index: 10000; position: fixed; display: block; height: 100%; width: 100%; background: #fff;} noscript .fa{font-size: 40px; display:block; color: #daa520;} noscript div{margin-top: 6%; padding-left: 20px; padding-right: 20px; text-align: center;} ! You must have JavaScript enabled to use this site.

Recommended

Tests

An error ocurred, try again later!

Chapter {{ article.chapter.number }}

{{ article.number }}.

Show less Show more

Lesson Settings & Tools

	{{ 'ml-lesson-number-slides' \| message : article.intro.bblockCount }}
	{{ 'ml-lesson-number-exercises' \| message : article.intro.exerciseCount }}
	{{ 'ml-lesson-time-estimation' \| message }}

Image Credits

{{ item.file.title }}
{{ presentation }}

No file copyrights entries found

Theory

Factor out the negative

A difference can be rewritten by factoring out the negative and changing the order of the terms.

5 - x = - (- 5 + x) = - (x - 5)

Thus, it's actually two steps, but can be done simultaneously.

Loading content

{{ article.displayTitle }}