5A-3B-[-A-(2B-5A)]=5A-3B+A+2B-5A=A-B
=-3m³-3/5m²+m-1-[(-3m³+2/5m²-m)+3]
=-3m³-3m²/5+m-1+3m³-2m²/5+m-3
=-m²+2m-4