已知a=-3,b=−1/4,c=2.5,求式子3a3-2b2+3c2-(-523/8)的值.

问题描述:

已知a=-3,b=

1
4
,c=2.5,求式子3a3-2b2+3c2-(-52
3
8
)的值.

将a=-3,b=

1
4
,c=2.5代入式子3a3-2b2+3c2-(-52
3
8
)得:
3a3-2b2+3c2-(-52
3
8

=3×(−3)3−2×(−
1
4
)2+3×2.52+52
3
8

=−81−
1
8
+
75
4
+52
3
8

=−81−
1
8
+
150
8
+
419
8

=-81+71
=-10.