75×4.7＋15.9×25
=(3×25)×4.7+15.9×25
=3×4.7×25+15.9×25
=(3×4.7+15.9)×25
=(14.1+15.9)×25
=30×25
=750
或者
75×4.7+(5.3×3)×25
=75×4.7+5.3×75
=75×(4.7+5.3)
=75×10
=750