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=−
,c=2.5,求式子3a3-2b2+3c2-(-521 4
)的值. 3 8
答
将a=-3,b=−
,c=2.5代入式子3a3-2b2+3c2-(-521 4
)得:3 8
3a3-2b2+3c2-(-52
)3 8
=3×(−3)3−2×(−
)2+3×2.52+521 4
3 8
=−81−
+1 8
+5275 4
3 8
=−81−
+1 8
+150 8
419 8
=-81+71
=-10.