计算下面各题.
(1)递等式计算:
36÷〔(-)×3〕
(2)解方程:
17.5-5(x+0.5)=9x?
(3)简便计算:(87.2+87.2+87.2×2)×25765×213÷27+765×327÷27.
网友回答
解:(1)36÷〔(-)×3〕,
=36÷〔×3〕,
=36÷,
=24;
(2)17.5-5(x+0.5)=9x,
??????? 17.5-5x-2.5=9x,
????????????? 15-5x=9x,
?????????? 15-5x+5x=9x+5x,
????????????????14x=15,
??????????? 14x÷14=15÷14,
???????????????? x=;
(3)(87.2+87.2+87.2×2)×25,
=87.2×(1+1+2)×25,
=87.2×4×25,
=87.2×(4×25),
=87.2×100,
=8720;
765×213÷27+765×327÷27,
=765×(213÷27+327÷27),
=765×[(213+327)÷27],
=765×[540÷27],
=765×20,
=15300.
解析分析:(1)先算减法,再算乘法,最后算除法;(2)根据等式的性质进行解答即可;(3)根据乘法交换律和结合律以及乘法分配律进行计算.
点评:四则运算,先弄清运算顺序,然后再进行计算即可,能简算的要简算,解方程要根据等式的性质进行解答.