4n/4n-4 × n-1/n+1
= 4n(n-1)/(4n-4)(n+1)
= (4n^2 - 4n)/(4n^2 + 4n - 4n-4)
= (4n^2 - 4n)/(4n^2 - 4)
= 4(n^2 - n)/4(n^2 - 1)
=(n^2 - n)/(n^2 - 1)
It's 12/35 because tangent is opposite over adjacent, so 12 is opposite of angle M and 35 is adjacent of angle M
If you want to remember cosine, sine, and tangent just remember
SOH CAH TOA
B is the right answer to this question