#### Answer

$x=5$

#### Work Step by Step

Let x = the unknown number
Then
"9 times a number" means $9x$
"30 more than 3 times a number" means $30+3x$
Thus, the equation that represents the situation is:
$9x=30+3x$
Use the addition property of equality to subtract 3x from both sides of the equation.
$9x-3x=30+3x-3x$
$6x=30$
Use the multiplication property of equality to divide both sides of the equation by 6.
$6x\div6=30\div6$
$x=5$