Answer:
[tex]\sf -3- \sqrt{5}[/tex]
Step-by-step explanation:
Simplify irrational numbers:
To simplify, use FOIL method.
[tex]\sf (2 + \sqrt{5})(1 - \sqrt{5})= 2*1 + (2)*(- \sqrt{5})+ ( \sqrt{5})*1+ \sqrt{5}*(- \sqrt{5})[/tex]
[tex]\sf = 2-2 \sqrt{5}+ \sqrt{5}- \sqrt{5*5}\\\\\\=2- 2 \sqrt{5}+ \sqrt{5}-5\\\\=2-5 - 2 \sqrt{5}+ \sqrt{5}\\\\\text{Combine like terms,}\\\\= -3 - \sqrt{5}[/tex]
