(7а)/(6с)–(49a2+36c2)/(42ac)+(6c–49a)/(7a)=(7a·7a–(49a2+36c2)+6c(6c–49a))/(42ac)=(49a2–49a2–36c2+36c2<span>–294ac)/(42ac)=(–294ac)/(42ac)=–7</span>
а)=23х³-14х²у+6х³-16х²у+4=29х³-30х²у+4
б)=2у^4-12у^4+6y^4-8y^4-11=-12y^4-11
в)=-20х^5-6x^5+27x^5-x^6=x^5-x^6
г)=-16а³b+18a³b-12a²b+14a²b=2a³b+2a²b
15*((40-(40:4)):2)=225; сначала 40:4 потом 40-10=30:2=15 после 15*15=225
15*40-40:4:2=0
15*40-(40:(4:2))=580