Question

Find the value of x and if necessary, express answer in simplest radical form.

Answer 1

Writing and solving an equation of ratios is the way to go here.  See if you can figure out why the following is correct:

x+3      x
----- = -------
  12     x+3

Then (x+3)^2 = 12x, and x^2 + 6x + 9 = 12x, so that x^2 - 6x + 9 = 0

This is the square of (x - 3).  Thus, x-3 = 0, and x = 3.

The value of x is 3.