T4:(2ab+bc+8ac)-(ab-2bc+3ac)
=2ab+bc+8ac-ab+2bc-3ac
=ab+3bc+5ac (A的结果)
(ab+3bc+5ac)-(ab-2bc+3ac)
=ab+3bc+5ac-ab+2bc-3ac
=5bc+2ac (正确结果)
T2:a+(n-1)乘2
T3:亏本
T4:(2ab+bc+8ac)-(ab-2bc+3ac)
=2ab+bc+8ac-ab+2bc-3ac
=ab+3bc+5ac (A的结果)
(ab+3bc+5ac)-(ab-2bc+3ac)
=ab+3bc+5ac-ab+2bc-3ac
=5bc+2ac (正确结果)
T2:a+(n-1)乘2
T3:亏本