Question

Тут Одно задание. Немогу решить, помогите а!!! 22 балла даю!!!!

Answer 1

$\dfrac{15a+2,5b}{9a^2-1,5ab}-\dfrac{15a-2,5b}{9a^2+1,5ab}+\dfrac{60a}{9a^2-0,25b^2}=\\\\\\=\dfrac{2,5\, (6a+b)}{1,5a\, (6a-b)}-\dfrac{2,5(6a-b)}{1,5a(6a+b)}+\dfrac{60a}{(3a-0,5b)(3a+0,5b)}=\\\\\\=\dfrac{2,5\, (6a+b)^2-2,5(6a-b)^2}{1,5a\, (6a-b)(6a+b)}+\dfrac{60a}{(3a-0,5b)(3a+0,5b)}=\\\\\\=\dfrac{2,5\, (36a^2+12ab+b^2-36a^2+12ab-b^2)}{1,5a\, (6a-b)(6a+b)}+\dfrac{60a}{(3a-\dfrac{b}{2})(3a+\dfrac{b}{2})}=$

$=\dfrac{60ab}{1,5a\, (6a-b)(6a+b)}+\dfrac{4\cdot 60a}{(6a-b)(6a+b)}=\\\\\\=\dfrac{40b}{(6a-b)(6a+b)}+\dfrac{4\cdot 60a}{(6a-b)(6a+b)}=\\\\\\=\dfrac{40b+240a}{(6a-b)(6a+b)}=\dfrac{40\, (b+6a)}{(6a-b)(6a+b)}=\dfrac{40}{6a-b}$