Answer:
1. [tex]4\sqrt{5}[/tex]
2. [tex]10\sqrt{10}[/tex]
Step-by-step explanation:
When you multiply radicals, you do the following
[tex]a\sqrt{b}\cdot c\sqrt{d}\\\\=ac\sqrt{bd}[/tex]
with that in mind
1.
[tex]\sqrt{16}\cdot \sqrt{5}[/tex]
here we don't need to multiply 16 times 5, because 16 = 4^2 and take the square root of it, gives you 4
[tex]=4\sqrt{5}[/tex]
2.
[tex]\sqrt{20}\cdot 5\sqrt{2}\\\\\longrightarrow 20 = 2^2\cdot 5\\\\=2\sqrt{5}\cdot5\sqrt{2}\\\\=(2\cdot5)\sqrt{5\cdot2}\\\\=10\sqrt{10}[/tex]
