Show that √5×√20 is an integer?

Answer:
See below.
Step-by-step explanation:
1) Simplify √20 to 2√5.
√5 × 2√5
2) Simplify.
2√5×5
3) Simplify 5 × 5 to 25.
2√25
4) Since 5 × 5 = 25, the square root of 25 is 5.
2 × 5
5) Simplify.
10
When evaluated, this expression equals a positive whole number, therefore showing it is a integer.