I need help please explain because I still don't get it

Which expressions are equivalent to k/2 choose 2 answers: a k-2 b 2/k c 1/2k d k/2 e k+k

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1

The sum of these consecutive integers is equal to 9 less than 4 times the least of the integer. find the three integers