New Problem

krisolaw

New member
Joined
Jun 5, 2005
Messages
45
Perform the operations and simplify when possible:

a/(a-b) + b/(a + b) + (a^2 + b^2)/(b^2 - a^2)

Please show me! Thanks in advance!
 

tkhunny

Moderator
Staff member
Joined
Apr 12, 2005
Messages
9,790
krisolaw said:
a/(a-b) + b/(a + b) + (a^2 + b^2)/(b^2 - a^2)
Change it to this:

a/(a-b) + b/(a + b) - (a^2 + b^2)/(a^2 - b^2)

The Least Common Denominator should now be obvious.
 

krisolaw

New member
Joined
Jun 5, 2005
Messages
45
Change it to this:

a/(a-b) + b/(a + b) - (a^2 + b^2)/(a^2 - b^2)

The Least Common Denominator should now be obvious.
I have this:
a/(a-b) + b/(a+b) - (a^2 + b^2)/(a +b)(a-b) LCD is now (a +b)(a - b)
[a(a+b) + b(a - b) - (a ^2 + b ^2)]/(a + b)( a - b) then:
(a ^2 + ab + ab - b^2 -a^2 - b^2)/(a + b)(a - b) so combine like terms:
(2ab - 2b^2)/(a +b)(a - b) then:
2b(a-b)/(a+b)(a-b)
answer: 2b/(a+b)

Please check! Thanks again!!! :)
 

Denis

Senior Member
Joined
Feb 17, 2004
Messages
1,473
Correct!

By the way, this 2b(a-b)/(a+b)(a-b) needs another set of brackets:
2b(a-b) / [(a+b)(a-b)]

Example:
20/2*5 = 50
20/(2*5) = 2 : quite a difference, hey?
 
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