How do you simplify \frac{((a+b)\div a)-\frac{b}{a+b}}{a+b}+\frac{\frac{b}{a}-\frac{a-b}{a+b}}{a-b}?

1 Answer
Nov 14, 2017

-b/(a(a-b))

(Get ready! It's a long one.)

Explanation:

Rewrite the expression.

(((a+b)/a)-b/(a+b))/(a+b)+(b/a-(a-b)/(a+b))/(a-b)

Point your focus to the fractions in the numerators. Add each set of fractions by multiplying by either a or a+b.

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

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

Simplify the complex fractions by multiplying by 1/(a+b) or 1/(a-b).

(1/(a+b))(((a+b)^2-b(a+b))/(a(a+b)))+(1/(a-b))((b(a+b)-a(a-b))/(a(a+b)))

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

Simplify.

(a+b-b)/(a(a+b))+(b(a+b)-a(a-b))/(a(a+b)(a-b))

a/(a(a+b))+(b(a+b)-a(a-b))/(a(a+b)(a-b))

Multiply a/(a(a+b)) by (a-b)/(a-b) to combine the fractions.

(a(a-b)-b(a+b)-a(a-b))/(a(a+b)(a-b))

Simplify.

(-b(a+b))/(a(a+b)(a-b))

-b/(a(a-b))