若a=-6.5,b=-12.7,c=29求)(a-b)-c和a+b-c的值.
问题描述:
若a=-6.5,b=-12.7,c=29求)(a-b)-c和a+b-c的值.
答
(1)(a-b)-c
=[-6.5-(-12.7)]-29
=[-6.5+12.7]-29
=6.2-29
=-22.8
(2)a+b-c
=(-6.5)+(-12.7)-29
=-19.2-29
=-48.2