计算①﹙2a+3b﹚2·﹙3b-2a﹚ ②﹙z-2x-y﹚2-﹙﹣z+2x+y﹚2 ③﹙m+2y﹚³ ④﹙3m-n﹚³

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/03 13:26:39
计算①﹙2a+3b﹚2·﹙3b-2a﹚ ②﹙z-2x-y﹚2-﹙﹣z+2x+y﹚2 ③﹙m+2y﹚³ ④﹙3m-n﹚³

计算①﹙2a+3b﹚2·﹙3b-2a﹚ ②﹙z-2x-y﹚2-﹙﹣z+2x+y﹚2 ③﹙m+2y﹚³ ④﹙3m-n﹚³
计算①﹙2a+3b﹚2·﹙3b-2a﹚ ②﹙z-2x-y﹚2-﹙﹣z+2x+y﹚2 ③﹙m+2y﹚³ ④﹙3m-n﹚³

计算①﹙2a+3b﹚2·﹙3b-2a﹚ ②﹙z-2x-y﹚2-﹙﹣z+2x+y﹚2 ③﹙m+2y﹚³ ④﹙3m-n﹚³
①﹙2a+3b﹚2·﹙3b-2a﹚ ²
=[(3b+2a)(3b-2a)]²
=(9b²-4a²)²
=81b的4次方-72a²b²+16a的4次方
②﹙z-2x-y﹚2-﹙﹣z+2x+y﹚2
=(z-2x-y)²-(z-2x-y)²
=0
③﹙m+2y﹚³
=m³+6m²y+12my²+8y³
④﹙3m-n﹚³=27m³-27m²n+9mn²-n³