((c+6b)/(ac+2cb-6ab-3a^2))+(2b/(a^2+2ab))-(b/(ac-3a^2)) желательно подробно) если можно

$\frac{c+6b}{ac+2cb-6ab-3a^{2}} +\frac{2b}{a^{2}+2ab} -\frac{b}{ac-3a^{2}}=$

$=\frac{c+6b}{c(a+2b)-3a(2b+a)}+\frac{2b}{a(a+2b)}-\frac{b}{a(c-3a)}=$

$=\frac{c+6b}{(a+2b)(c-3a)}+\frac{2b}{a(a+2b)}-\frac{b}{a(c-3a)}=$

$=\frac{a(c+6b)+2b(c-3a)-b(a+2b)}{a(a+2b)(c-3a)}=\frac{ac+6ab+2bc-6ab-ab-2b^{2}}{a(a+2b)(c-3a)}=$

$=\frac{ac-ab+2bc-2b^{2}}{a(a+2b)(c-3a)}=\frac{(ac+2bc)-(ab+2b^{2})}{a(a+2b)(c-3a)}=\frac{c(a+2b)-b(a+2b)}{a(a+2b)(c-3a)}=$

$=\frac{(a+2b)(c-b)}{a(a+2b)(c-3a)}=\frac{c-b}{a(c-3a)}$