Question

If K = (AB)/(A+B) , then B = ?

(a) (A)/(1−A)
(b) (AK)/(A−K)
(c) (AK)/(K−A)
(d) (A+K)/(A)
(e) (A−K)/(AK)

Answer 1

Lets do

`\\ \sf\longmapsto K=(AB)/(A+B)`

`\\ \sf\longmapsto (1)/(K)=(A+B)/(AB)`

`\\ \sf\longmapsto (1)/(K)=(1)/(A)+(1)/(B)`

`\\ \sf\longmapsto (1)/(B)=(1)/(K)-(1)/(A)`

`\\ \sf\longmapsto (1)/(B)=(K-A)/(AK)`

`\\ \sf\longmapsto B=(AK)/(K-A)`