Question 46387
Since x^2 will be the first to factor you make two sets of parathesis and put x as the first factor in each
(x   )(x   )
Next you have to figure out which numbers that make -18 will also come out to a -3 when you add or subtract.
For example, the factors of 18 are 1, 2, 3, 6, 9, 18.  Which of those numbers could make a negative 3?  A negative 6 and a positive 3 will make a -3 when you add them, and it will make a -18 when you multiply them.  So heres how you finish the problem...
(x-6)(x+3)
To check your answer, FOIL it out.