Question 871202
You need to learn the FOIL Method.
That's how you get from factors to quadratic.
Example:
{{{(x-3)(x+1)}}}
First: {{{x*x=x^2}}}
Outer:{{{x(1)=x}}}
Inner:{{{-3(x)=-3x}}}
Last:{{{-3(1)=-3}}}
Now add it up.
{{{(x-3)(x+1)=x^2+x-3x-3}}}
{{{(x-3)(x+1)=x^2-2x-3}}}
So now quickly checking, since the last two entries of the factors are (-3)(1), the constant term of the quadratic is (-3). 
So now for each answer, what is the constant terms (remember there is a multiplier in front of each set of factors).
A.{{{4(-3)(1)=-12}}}
B.{{{5(-1)(3)=-15}}}
C.{{{-3(-4)(2)=24}}}
D.{{{-2(-3)(3)=18}}}
Check against the quadratic equation.
A.{{{1<>-12}}}
B.{{{-15=-15}}} Possible
C.{{{-8<>24}}}
D.{{{18=18}}} Possible
OK, now look at the x term, the coefficient of x is always twice the sum of the last two entries of the factor. Look at those for the possible answers from before. Again remember the multiplier in front of the factors.
B.{{{5(2(-1+3))=5(2(2))=20}}}
D.{{{-2(2(-3+3))=-2(2(0))=0}}}
Now compare again with the quadratic equations looking for the x term.
B. {{{-10<>20}}}
D.{{{0=0}}} Here's your answer.
{{{highlight(-2x^2+18=-2(x-3)(x+3))}}}
It's good practice to work the FOIL method forwards and backwards until you become comfortable using it.