问题
解答题
化简求值:3a2+4(a2-2a-1)-2(3a2-a+1),其中a=-
|
答案
3a2+4(a2-2a-1)-2(3a2-a+1)
=3a2+4a2-8a-4-6a2+2a-2
=a2-6a-6
当a=-
时,原式=(-1 2
)2-6×(-1 2
)-61 2
=
+3-61 4
=-
.11 4
化简求值:3a2+4(a2-2a-1)-2(3a2-a+1),其中a=-
|
3a2+4(a2-2a-1)-2(3a2-a+1)
=3a2+4a2-8a-4-6a2+2a-2
=a2-6a-6
当a=-
时,原式=(-1 2
)2-6×(-1 2
)-61 2
=
+3-61 4
=-
.11 4