SOLUTION: Need help solving a practice problem, I cannot get this one right! (5x+3) / (3x)= (7 / 3) - (9 / x) I tried multiplying (7 / 3)(x / x) and (9 / x)(3 / 3) to get the right s

Algebra ->  Expressions-with-variables -> SOLUTION: Need help solving a practice problem, I cannot get this one right! (5x+3) / (3x)= (7 / 3) - (9 / x) I tried multiplying (7 / 3)(x / x) and (9 / x)(3 / 3) to get the right s      Log On


   

Question 58037: Need help solving a practice problem, I cannot get this one right!
(5x+3) / (3x)= (7 / 3) - (9 / x)
I tried multiplying (7 / 3)(x / x) and (9 / x)(3 / 3) to get the right side to become:
(7x-27) / (3x) but then I thought I could just get rid of the denominators since they were the same and I'd be left with (5x+3) = (7x-27), which eventually gives an answer of 15. However, when I check the solution of 15 in the original problem it doesn't work out. What am I doing wrong?
Thanks!
Karen
Found 2 solutions by funmath, tutorcecilia:
Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
Hi Karen,
Your solution is right, so I'm going to show you the checking part.
(5x+3) / (3x)= (7 / 3) - (9 / x)
I tried multiplying (7 / 3)(x / x) and (9 / x)(3 / 3) to get the right side to become:
(7x-27) / (3x) but then I thought I could just get rid of the denominators since they were the same and I'd be left with (5x+3) = (7x-27), which eventually gives an answer of 15.
%287%2815%29-27%29%2F%283%2815%29%29=%287%2F3%29-9%2F15
%28105-27%29%2F45=7%2A5%2F%283%2A5%29-9%2F15
78%2F45=35%2F15-9%2F15
3%2A26%2F%283%2A15%29=%2835-9%29%2F15
26%2F15=26%2F15 You're right.
Checking this kind of problem is a bear, unless you reduce both sides completely, you won't know both sides are equal. I usually like to check these things by storing values into my graphing calculator. Which gave me 1.7333...=1.7333... proving you were right.
Happy Calculating, Karen!!!

Answer by tutorcecilia(2152) About Me  (Show Source):
You can put this solution on YOUR website!
(5x+3) / (3x)= (7 / 3) - (9 / x) [You have the right answer,]
(5(15)+3) / (3(15))= (7 / 3) - (9 /(15))
75+3/45=7/3-9/15
1.733=1.733 [checks out]