Question

УПРОСТИТЕ ВЫРАЖЕНИЕ1!!!!!!!!!!!!!!!!!!!

Answer 1

$1)frac{a-3b}{a^{2}+3ab }-frac{a+3b}{a^{2} -3ab}=frac{a-3b}{a(a+3b)}-frac{a+3b}{a(a-3b)}=frac{a^{2} -6ab+b^{2}-a^{2}-6ab-b^{2}}{a(a+3b)(a-3b)}=frac{-12ab}{a(a^{2}-9b^{2})} \\2)-frac{12ab}{a(a^{2}-9b^{2})}:frac{4b^{2}}{9b^{2}-a^{2}}=frac{12ab}{a(9b^{2}-a^{2})}*frac{9b^{2}-a^{2}}{4b^{2}}=frac{3}{b}$