Write and solve an equation based off the verbal phrase. the sum of x and 9 is divided by 2. that quantity is equal to 3x.

Start with the sum of x and 9, giving the expression

This is divided by 2 so

This equals 3x so the equation is

This can the be solved.
Multiply both sides by 2 to get

Then take x from both sides

Divide by 5 to get the value for x