(a – b +
4ab/ a – b) = (a-b)^2 +4ab /a-b = a^2 –
2ab + b^2 + 4ab /a – b =
(a + b)^2/a-b
4a^2 /(a + b)^2
– 2a/ a+ b = 4a^2 - 2a( a+ b )/(a + b)^2 = 4a^2 - 2a^2
- 2ab /(a + b)^2= 2a^2 - 2ab /(a + b)^2
((a + b)^2/a-b)
* (2a^2 - 2ab /(a + b)^2) = ((a + b)^2 *
(2a^2 - 2ab)/(a-b) * (a + b)^2 = (2a^2 - 2ab)/(a-b) = 2a (a - b)/(a-b) = 2a