1.a.(a-2)(a-3) = a²-3a-2a+6=a²-5a+6
b.(5x+4)(2x-1)=10x²-5x+8x-4=10x²+3x-4
в.(3p+2c)(2p+4c)=6p²+12pc+4cp+8c²=6p²+8c²+16pc
г.(b-2)(2b+2b-3)=2b²+2b²-3b-4b-4b+6=2b²+2b²-11b+6
2.x(x-y)+a(x-y)=(x-y)(x+a)
2a-2b+ca-cb=(2a+ca)-(2b+cb)=a(2+c)-b(2+c)=(2+c)(a-b)