(x/x+y)+(x/x-y)
What you typed means this
x x
--- + y + --- - y
x x
I'm sure that's not what you meant as that is too easy:
1 + y + 1 - y
which equals 2.
You didn't put in enough parentheses. To type an expression all on one line,
you must begin every numerator and every denominator with a "(" and end it with
a "}"; otherwise you cannot tell where it starts and ends. The only times you
don't need a pair of parentheses around a numerator or denominator is when it
contains only one number or one letter.
What I think you meant was this
x x
----- + -----
x+y x-y
which you should have typed on one line as:
x/(x+y) + x/(x-y)
==========================================
x x
----- + -----
x+y x-y
When the denominators have no common factor, as here, you may use
this rule:
A C AD ± CB
--- ± --- = ---------
B D BD
x x x(x-y) + x(x+y)
----- + ----- = ----------------- = (CAREFUL! NO CANCELLING BETWEEN
x+y x-y (x+y)(x-y) NUMERATOR AND DENOMINATOR ALLOWED HERE!)
x² - xy + x² + xy
-----------------
(x+y)(x-y)
2x²
------------
(x+y)(x-y)
Edwin
AnlytcPhil@aol.com