Question

已知a²－a－4=0,求a²－2(a²-a＋3)-½(a²－a-4)－a的值

Answer 1

已知a2-a-4=0,则a2-a=4
a2-2(a2-a+3)-1/2(a2-a-4)-a
=a2-2(4+3)-1/2(4-4)-a
=a2-14-a
=a2-a-14
=4-14
=-10

追问

嗯，非常感谢。