1.原式=15+3-3a-1+a+a²+1-a+a²-a³=18-3a+2a²-a³2.原式=4a²b-3ab-5a²b+2ab=-a²b-ab3.原式=6m²-4m-3+2m²-4m+1=8m²-8m-24.原式=5a²+2a-1-12+32a-8a²=-3a²+34a-135.原式=3x²-5x+0.5x-3-2x²=x²-4.5x-3