Question

If `c=(2ab)/(a+b)` then `b=`?

Answer 1

`color(blue)(b=(ac)/(2a-c)`

Explanation:

`c=(2ab)/(a+b)`

`color(white)("XXX")rArr c(a+b)=2ab`

`color(white)("XXX")rArr ac=2ab-cb`

`color(white)("XXX")rArr ac = (2a-c)b`

`color(white)("XXX")rArr b=(ac)/(2a-c)`

Note: in order to obtain a meaningful result we have needed to assume (for example) `2a-c!=0`