Question 88164
This is called "completing the square".  Assuming that the coefficient of the x^2 term is 1, you take HALF of the x coefficient, and SQUARE it.  In this case, take HALF of 18 (which is 9) and SQUARE (which is 81). 


Now you have 
{{{x^2+18x+ 81}}} 
{{{(x+9)^2}}}


The final answer is 81.  


R^2