2右2/9—(2/9+5/12) 、（2/17+1/13）×17×39 递等式计算,谢谢

Question

如题所述

Answer 1

2右2/9—(2/9+5/12)
=2又2/9-2/9-5/12
=2-5/12
=1又7/12
（2/17+1/13）×17×39
=2/17×17×39+1/13×17×39
=2×39+3×17
=78+51
=129