1.解:(1)4a-2(b-3c)=4a-2b+6c. (2)-5a+1/2(4x-6)=-5a+2x-3.
(3)3x+【4y-(7z+3)】=3x+(4y-7z-3)=3x+4y-7z-3. (4)-3a³-【2x²-(5x+1)】=-3a³-(2x²-5x-1)=-3a³-2x²+5x+1.
2.解:(1)(8x-5y)-(4x-9y)=8x-5y-4x+9y=4x+4y. (2)x-(2x-y)+(3x-2y)=x-2x+y+3x-2y=2x-y. (3)2(x+y)+(-5x+2y)=2x+2y-5x+2y=4y-3x. (4)(3a²-b²)-3(a²-2b²)=3a²-b²-3a²+6b²=5b².
(5)-2(-3xy+2z)+3(-2xy-5x)=6xy-4z-6xy-15x=-4z-15x.