The idea is to find out which square root all the terms can be factored into, then you usually end up with the square root of a perfect square (an integer that is the square of another integer). Then you can take the square root of that perfect square (for each term) and you get multiples of the same square root that you can add together. In this question, the second term already has the first couple steps done, so it gives you a hint of what square root to convert the others into.

sqrt45 + 5sqrt5 + sqrt20

= sqrt(9)*sqrt(5) + 5*sqrt(5) + sqrt(4)*sqrt(5)

=3sqrt(5)+5sqrt(5)+2sqrt(5)

=10sqrt(5)

I don't understand what the capital V stands for, but assuming the following equation is the one you need to solve, then the solution is as follows:

x+9=3-x

x+x+9=3

2x=-6

x=-3