Solve For x...2

Revisiting precalculus just for fun.
Enjoy.

 

1/x=1/a+1/b.........common denominator is ab
1/x=b/(ab)+a/(ab)
1/x=(b+a)/(ab)..........cross multiply
ab=x(b+a)........isolate x
x=(ab)/(b+a)

check:

1/x=1/a+1/b......substitute x

1/((ab)/(b+a))=1/a+1/b

(b+a)/(ab)=1/a+1/b
b/(ab)+a/(ab)=1/a+1/b
1/a+1/b=1/a+1/b-> confirmed

 

Nice work as always. Thank you. I posted enough math questions for today. There are many threads still unanswered. I will wait for you to respond.