求未知数x
x+218=500????????372-x=162????????x÷15=80????????141÷x=47.
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解:(1)x+218=500,
???? x+218-218=500-218,
???????????? x=282;
(2)372-x=162,
?? 372-x+x=162+x,
?????? 372=162+x,
???372-162=162+x-162,
???????? x=210;
????????
(3)x÷15=80,
?x÷15×15=80×15,
???????? x=1200;
????????
(4)141÷x=47,
? 141÷x×x=47×x,
??? 141÷47=47x÷47,
??????????x=3.
解析分析:依据等式的性质:(1)两边同时减218求解,(2)两边同时加x,再同时减162求解,(3)两边同时乘15求解,(4)两边同时乘x,再同时除以47求解.
点评:本题主要考查学生依据等式的性质求解知识的掌握.