reducing 6y/-12y^2=1/-2y ?

Question

or -2y?

Answer 1

1/-2y

Factors of numerator are 6 and y
Factors of denominator -1, 2, 6 y and y
the 6's cancel out, one of the y's cancel out

you are left with 1 x 1 = 1 0n the top line
and -1,2 and y on the bottom line. = -2y
Hence your answer.