Question

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

Answer 1

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

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

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

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

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

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

(2) [1-1/(1-X) ] ÷X/X-1

=(1-x-1)/(1-x)*(x-1)/x

=(-x)/(1-x)*(x-1)/x

=x/(x-1)*(x-1)/x

=1