X + y = 21
(x - y) = 2x - 6
Rewrite the first equation so that y = 21 - x
Now substitute y in the second equation, and solve for x.
Then solve for y
Practically speaking, both of them are correct. Technician A who uses an oxy-acetylene torch to remove oil galley plugs would spend more time than Technician B (assuming he uses a drill with appropriate drill bit size). Technician A would induce heat via the torch to expand the hole in the engine block. Doing this would allow the stubborn oil galley plugs slip out the hole easily. Adding paraffin wax at the other end would speed up the removal. Technician B should initially use a smaller size drill bit to provide a pilot hole then proceed with square head bit to detach the plug.
Answer:
we can't write papers for you, it's for questions
This is called cluster sampling, where the researcher divides the population into groups (clusters) then takes a random sample from among the different clusters.
