Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: if ( c - a ) / ( c - b ) = 1 , then ( 5 b - 4 a ) / ( c - a ) =
0.5
5b-4a/c-a = (5b-4a)/(c-b) = 5b/(c-