Imagine that a new operational symbol for mathematics has been developed. This symbol is ~ and is represented by:
a~b=ab/a-b
Using this new symbol, find the value of :(2~3)~4.
Just plug in.
2~3 becomes 2*3/(2-3) = -1, and
-1~4 becomes -1*4/(-1-5) = -4/-6 = 2/3