#### Answer

{9}

#### Work Step by Step

5x = 45
Step 1: Divide both the sides by 5
$\frac{5x}{5}$ = $\frac{45}{5}$
Step 2: Simplify
x= 9
Now we check the proposed solution, 9, by replacing x with 9 in the original equation.
Step 1: the original equation 5x = 45
Step2: Substitute 9 for x
5.9 = 45
Step 3: Solve 5.9=45
45 = 45
Since the check results in true statement, we conclude that the solution set of the given equation is {9}.