SOLUTION: I am a parent helping with homework. I am stumped on this one: Solve for r: S=(rL-a)/(r-1)

Algebra ->  Expressions-with-variables -> SOLUTION: I am a parent helping with homework. I am stumped on this one: Solve for r: S=(rL-a)/(r-1)      Log On


   

Question 12244: I am a parent helping with homework. I am stumped on this one:
Solve for r: S=(rL-a)/(r-1)
Answer by AdolphousC(70) About Me  (Show Source):
You can put this solution on YOUR website!
This one seems confusing at first, but you just need to get the two r terms together so you can factor them out, here is how I did the problem


+S+=+%28rL-a%29%2F%28r-1%29+ Mulitply (r-1) to get it out of the denominator
+%28r-1%29S+=+rL-a+ Distribute the S through r-1
+rS+-+S+=+rL+-+a+ now we need to get both r terms on one side of the equation so we can take the GCF of 'r' out
  • so we subtract rL from both sides
  • add S to both sides
    +rS+-+rL+=+S+-+a+ Factor out the r on the left
    +r%28S+-+L%29+=+S+-+a+ Divide both sides by S - L
    +r+=+%28S-a%29%2F%28S-L%29+
    Hope that helps, Mr. C