化简后求值5a^3-2/15(3b^2+5a^3 )+(4b^2+2ab )其中a=-1,b=1/2

问题描述:

化简后求值5a^3-2/15(3b^2+5a^3 )+(4b^2+2ab )其中a=-1,b=1/2

原式=5a³-2/5b²-2/3a³+4b²+2ab
=13/3a³+18/5b²+2ab
=-13/3+9/10-1
=-133/30