⑸3x²+[2x-﹙-5x²+4x﹚+2]-1

问题描述:

⑸3x²+[2x-﹙-5x²+4x﹚+2]-1
⑹﹙9a-2b﹚-[8a-﹙5b-2c﹚]+2c
⑺4a²-[a²+﹙4a²-2a﹚-2﹙a²-3a﹚]
⑻3/4 [4/3﹙1/3x-1﹚-8]-﹙-2/3x-5﹚

⑸3x²+[2x-﹙-5x²+4x﹚+2]-1=3x²+2x+5x²-4x+2-1=8x²-2x+1⑹﹙9a-2b﹚-[8a-﹙5b-2c﹚]+2c=9a-2b-8a+5b-2c+2c=a-3b⑺4a²-[a²+﹙4a²-2a﹚-2﹙a²-3a﹚]=4...