Mean is adding all the numbers then dividing the answer you go from the numbers.
3 Eggs: 4 times what equals 12? (We use 4 because its 1/4 or a quarter) 3 times 4 equals 12.
7 = 14x - 42y
42y = 14x - 7
y = (14x - 7)/ 42
or we could write it as y = (1/3)x - 1/6
You have to divide 400 by 5. That will equal 80. Since the ratio is 3:2 Just multiply 3 by 80 then 2 by 80! :-)
You can check it by simplifying it again.
What can you be more specific like a put it in a sentence. For example x*-260+7=?