①(2m+3)²=4m²+12m+9 ②（-1.3a+2b）²=1.69a²-5.2ab+4b²③（-2p-7q）²=(2p+7q)²=4p²+28pq+49q² ③（a-3分之1b）²=a²-2ab/3+b²/9