1.次の計算をせよ。
③ 8a2+12a-715-11a2-4a+920+4a-7
③ 8a2+12a-715-11a2-4a+920+4a-7
= 4(8a2+12a-7)60-3(11a2-4a+9)60+60(4a-7)60
= 4(8a2+12a-7)-3(11a2-4a+9)+60(4a-7)60
= 32a2+48a-28-33a2+12a-27+240a-42060
= (32-33)a2+(48+12+240)a-28-27-42060
= -a2+300a-47560
= -a260+5a-9512