Help geometry questions , need help on this test !!

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

He weights of 2-pound bags of best dog food are approximately normally distributed with a given mean  and standard deviation  according to the empirical rule, what percentage of the bags will have weights within 3 standard deviations of the mean? 47.5%68%95%99.7%

Asap (i need to finish this quick) graph complete the sequence of transformations that produces △x'y'z' from △xyz. a clockwise rotation ° about the origin followed by a translation units to the right and 6 units down produces δx'y'z' from δxyz.