∵a²>0
∴a≠0
∴若a²>0,a³为正数或负数.
-2.5×7.3+2.5×(-2.4)-2.5×(-1.7)
=2.5×(-7.3)+2.5×(-2.4)-2.5×(-1.7)
=2.5×(-7.3-2.4+1.7)
=2.5×(-8)
=-20
∵a²>0
∴a≠0
∴若a²>0,a³为正数或负数.
-2.5×7.3+2.5×(-2.4)-2.5×(-1.7)
=2.5×(-7.3)+2.5×(-2.4)-2.5×(-1.7)
=2.5×(-7.3-2.4+1.7)
=2.5×(-8)
=-20