а) (a+2)(b-3)= ab-3a+2b-6
б) -(3a-1)(2a+5)= (1-3a)(2a+5)= 2a+5-6a²-15a= -6a²-13a+5
в) (a+3b)(a²-6ab-b²)= a³-6a²b-ab²+3a²b-18ab²-3b³= a³-3a²b-19ab²-3b³
(a+2)(a-5)-3a(1-2a)= a²-5a+2a-10-3a+6a²= 7a²-6a-10
а) (a+2)(b-3)= ab-3a+2b-6
б) -(3a-1)(2a+5)= (1-3a)(2a+5)= 2a+5-6a²-15a= -6a²-13a+5
в) (a+3b)(a²-6ab-b²)= a³-6a²b-ab²+3a²b-18ab²-3b³= a³-3a²b-19ab²-3b³
(a+2)(a-5)-3a(1-2a)= a²-5a+2a-10-3a+6a²= 7a²-6a-10