STATISTICS: What was the sampling method: simple random, convenience, stratified, cluster, systematic, or voluntary, that was used in the 1998 MMR vaccine and autism study done by Andrew Wakefield?

Solve the equation x/4 - 5= -8 -27 -12 -7 12

We just started the introduction into circles and i have no idea how to do this.

Marcus and cody both leave the park at the same time, but in opposite directions. if cody travels 6 mph faster than marcus and after 4 hours they are 64 miles apart, how fast is each traveling? solve using rare times time = distance.