а) (3а-1)(2а+5)-6а²=6а²+15а-2а-5-6а² =13а-5
б)12b³-(4b²-1)(3b-2)=12в³-(12в³-8в²-3в+2)=12в³-12в³+8в²+3в-2=8в²+3в-2
а) (3а-1)(2а+5)-6а²=6а²+15а-2а-5-6а² =13а-5
б)12b³-(4b²-1)(3b-2)=12в³-(12в³-8в²-3в+2)=12в³-12в³+8в²+3в-2=8в²+3в-2