5A-3B-[-A-(2B-5A)]
=5A-3B+A+(2B-5A)
=6A-3B+2B-5A
=A-B
=(-3M^2+M-1)-[1/2(-6M^3+4/5M^2-2M)+3]
=-3M^2+M-1-1/2(-6M^3+4/5M^2-2M)-3
=-3M^2+M-4+3M^3-2/5M^2+M
=-2/5M^2+2M-4
5A-3B-[-A-(2B-5A)]
=5A-3B+A+(2B-5A)
=6A-3B+2B-5A
=A-B
=(-3M^2+M-1)-[1/2(-6M^3+4/5M^2-2M)+3]
=-3M^2+M-1-1/2(-6M^3+4/5M^2-2M)-3
=-3M^2+M-4+3M^3-2/5M^2+M
=-2/5M^2+2M-4