SOLUTION: I solved this problem and the teacher says it is wrong. Can you point out what is wrong and help me solve? 15/3y - (-80/10x) 5/y +8/x 13/xy

Algebra ->  Equations -> SOLUTION: I solved this problem and the teacher says it is wrong. Can you point out what is wrong and help me solve? 15/3y - (-80/10x) 5/y +8/x 13/xy      Log On


   



Question 186474: I solved this problem and the teacher says it is wrong. Can you point out what is wrong and help me solve?
15/3y - (-80/10x)
5/y +8/x
13/xy

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
15/3y - (-80/10x)
5/y +8/x
You cannot directly add fractions that have different denominators.
----
lcd = xy
Rewrite each fraction with the lcd as its denominator:
5x/lcd + 8y/lcd
Add to get:
(5x + 8y)/lcd
= (5x+8y)/xy
================
Cheers,
Stan H.