To solve for the values of X that will make the equation true, all you have to do is factor this trinomial. Basically find 2 numbers that multiply to give you 81 and also add to give you -18, in this case the numbers would be -9 and -9. Since -9 + -9 = -18 and -9 • -9 = 81. Thus the factored expression would be like this:
(X-9)(X-9) = 0
X - 9 = 0 and X - 9 = 0
In both cases the solutions for X is that X is equal to 9.
The value of X that will make this equation true, is if X is equal to 9.