If a = b /c-b , find the value of b when a = 3 and c = 10 *

An an average person has 6×10 by the power of two as many red blood cells as white blood cells a small sample of the blood has 7×10 by the power of three white blood cells about how many red blood cells are in the sample

Adifferent website gives the cost for the first train as £56.88 and the second train as £20.11 with a £9.50 charge for cycle storage for the whole trip. how much would the journey cost you?

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?