How to solve the equation by factoring 5x^2=45?

First, we'll have to move all terms to one
side:

5x^2 - 45 = 0

We'll
factorize by 5 to the left:

5(x^2 - 9) =
0

We'll divide by 5 both
sides:

x^2 - 9 = 0

We'll
re-write the difference of the squares as a
product:

(x-3)(x+3) = 0

We'll
cancel each factor:

x + 3 =
0

x = -3

x - 3 =
0

x =3

The
solutions of the equation are {-3 ; 3}.