It's 416,666,667/1,000,000,000. //// If you said that the 6s keep going and never end, then it would be the decimal form of 5/12 .
To simply the expression,we should remember an ! in math represents every number (til 1) before that one multiplied or "the product of the integers from 1 to n"
So now that we have the definitions we can simplify by finding the values of each:
(9x8x7x6x5x4x3x2x1)-(4x3x2x1)(5x4x3x2x1)
After simplifying this will equal to 3600
So, x = 13, x = √3 and x =7i.
now, recall that for an EVEN radical, there are two possible roots, namely is say √3 is say hmmm some value "a", that means that a*a = √3, however, -a*-a is also √3, therefore, ±√3 are two valid values, and therefore -√3 is another one.
now.... keep in mind that, complex solutions or roots, never come all by their lonesome, their sister is always with them, the conjugate, so, for 7i or namely 0 + 7i, her sister is always around, 0 - 7i, which is the other root.
The answer is the first choice.
P(both even) = (4P1)(3P1) / 9P2