If you've had a computer for any long period of time, you've probably encountered a computer virus. Find out exactly what computer virus are, and how they work in this video.

What you need to know about malware including the difference between computer viruses, worms, Trojans, ransomware and spyware.

Rotate to landscape screen format on a mobile phone or small tablet to use the **Mathway** widget, a free math problem solver that **answers your questions with step-by-step explanations**.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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