How do I get the answer??

Answer:
4√10
Step-by-step explanation:
Hello!
Let's first simplify the radical.
We can do this by expanding the radical:
We need to pull out a perfect square factor to expand a radical and simplify it. In 45, we have 9 and 5 multiplied, and 9 is a perfect square.
Let's work with √45:
Now we can simplify the operation in the parenthesis by combining like terms:
Now using the same rule as above, we can multiply the values:
Your solution is 4√10