SOLUTION: Please help me with this problem! 1/R=1/A+1/B (solve for B) According to the answers in the back of my textbook the answer is B = RA/A-R but I'm not sure how this is done.

Algebra ->  Equations -> SOLUTION: Please help me with this problem! 1/R=1/A+1/B (solve for B) According to the answers in the back of my textbook the answer is B = RA/A-R but I'm not sure how this is done.      Log On


   

Question 663050: Please help me with this problem!
1/R=1/A+1/B (solve for B)
According to the answers in the back of my textbook the answer is B = RA/A-R but I'm not sure how this is done.
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
1%2FR=1%2FA%2B1%2FB

1%2FR-1%2FA=1%2FB......on the left side find LCD

%281%2AA-1%2AR%29%2FRA=1%2FB

%28A-R%29%2FRA=1%2FB...........cross multiply

%28A-R%29B=1%2ARA

B=RA%2F%28A-R%29