To begin the process of simplifying radical expression, we must introduce the product and quotient rule for radicals
Product Rule for Radicals: If
and
are real numbers and
n is a natural number, then
That is, the product of two radicals is the radical of the product.
Example 1 - using product rule

Quotient Rule for Radicals: If
and
are real numbers,
and
n is a natural number, then
That is, the radical of a quotient is the quotient of the radicals.
Example 2 - using quotient rule

Exercise 1: Simplify radical expression
Level 1
Level 2
Example 2: Simplify
Solution:
Step 1: We need to find the largest perfect square that divides into 18. Such number is 9.
Step 2:Write 18 as the product of 2 and 9. ( 18 = 2 * 9 )
Step 3:Use the product rule: 
Example 3: Simplify
Solution:
Step 1: Again, we need to find the largest perfect square that divides into 108. Such number is 36.
Step 2:Write 108 as the product of 3 and 36. ( 108 = 3 * 36 )
Step 3:Use the product rule: 
Example 4: Simplify
Solution:
No perfect square divides into 15, so
cannot be simplified
Example 5: Simplify
Solution:
Step 1: Now, we need to find the largest perfect cube that divides into 24. Such number is 8.
Step 2:Write 24 as the product of 3 and 8. ( 24 = 3 * 8 )
Step 3:Use the product rule: 
Exercise 2: Simplify expression
Level 1
Level 2
Examples 6: In this examples we assume that all variables represent positive real numbers.
Exercise 3: Simplify expression
Level 1
Level 2
Please tell me how can I make this better?