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**icelated** Okay, so my book is horrible and it doesnt explain things very well and i cant seem to find my answer anywhere online.

I wont write out the example in the book since i think its irrelevant and way to long. I am struggling with the notation and how they get the answer.

$\displaystyle f(0) = P(X=0) = \frac{\left[\begin{array}{cc}3 \\0 \\\end{array}\right] \left[\begin{array}{cc}17 \\2 \\\end{array}\right]}{\left[\begin{array}{cc}20 \\2 \\\end{array}\right]} = \frac{68}{95} $

I m very confused on how they got the answer.

I think the (3 0 ) = 0?