解方程.
(1)(1-25%)x=72?????????????????????
(2)x-40%x=5.04
(3)x÷(1-40%)=3.6?????????????????????
(4)34x-25%x=12.
网友回答
解:(1)(1-25%)x=72,
???????????????75%x=72,
????????? 75%x÷75%=72÷75%,
????????????????? x=96;
(2)x-40%x=5.04,
?????? 60%x=5.04,
? 60%x÷60%=5.04÷60%,
????????? x=8.4;
(3)x÷(1-40%)=3.6,
?????????? x÷60%=3.6,
????? x÷60%×60%=3.6×60%,
??????????????? x=2.16;
(4)34x-25%x=12,
?????? 33.75x=12,
33.75x÷33.75=12÷33.75,
??????????? x=.
解析分析:(1)先化简方程,再依据等式的性质,方程两边同时除以75%求解,(2)先化简方程,再依据等式的性质,方程两边同时除以60%求解,(3)先化简方程,再依据等式的性质,方程两边同时乘60%求解,(4)先化简方程,再依据等式的性质,方程两边同时除以33.75求解.
点评:本题主要考查学生依据等式的性质解方程的能力,解方程时注意对齐等号.