Here's why:
* Informal: Slang is inherently informal and casual. It's often specific to a particular group or region and can be confusing or even offensive to a wider audience.
* Lack of Clarity: Slang terms can be ambiguous or have multiple meanings, making your writing unclear and difficult to understand.
* Unprofessional: Using slang in formal writing conveys a lack of professionalism and can undermine your credibility.
Formal writing requires clear, concise, and precise language. Using standard vocabulary and avoiding slang will ensure your writing is easily understood and taken seriously.