1)а/3а-1 - а/3а+1 = а(3а+1)-а(3а-1)/(3а-1)(3а+1)=3а^2+a-3a^2+a/(3а-1)(3а+1)=2а/(3а-1)(3а+1)
2)2а/(3а-1)(3а+1):6а/(3а+1)=2а/(3а-1)(3а+1)* (3а+1)/6а=1/9а-3
1)а/3а-1 - а/3а+1 = а(3а+1)-а(3а-1)/(3а-1)(3а+1)=3а^2+a-3a^2+a/(3а-1)(3а+1)=2а/(3а-1)(3а+1)
2)2а/(3а-1)(3а+1):6а/(3а+1)=2а/(3а-1)(3а+1)* (3а+1)/6а=1/9а-3