As your question is stated, there is no answer!
I'm going to assume the polynomial you meant is:
[tex] x^2 + \frac{2}{3} x [/tex]
To create a perfect square trinomial, take half the coefficient of x and then square it.
[tex] \left( \frac{1}{2} \times \frac{2}{3} \right) ^2 = \left(\frac{1}{3} \right) ^2 =\frac{1}{9} [/tex]
In all problems like this, you want to square half the coefficient of x -- always half.
