解方程
16×8-7x=235x+15=603x+x=883(x+9)=5460×0.4+6x=63.65x-7.2×5=123x+0.6x=28.8338-34x=42×4.
网友回答
解:①16×8-7x=23,
??? ?? 128-7x=23,
??? 128-7x+7x=23+7x,
??????? ? 128=23+7x,
?????23+7x-23=128-23,
??????? ?? 7x=105,
??????? 7x÷7=105÷7,
????????????x=15;
??
?②5x+15=60,
5x+15-15=60-15,
???? ?5x=45,
?? 5x÷5=45÷5,
???? ? x=9;
③3x+x=88,
??? 4x=88,
?4x÷4=88÷4,
?????x=22;
?
?④3(x+9)=54,
3(x+9)÷3=54÷3,
??????? x+9=18,
????? x+9-9=18-9,
??????? ? x=9;
⑤60×0.4+6x=63.6,
?????? 24+6x=63.6,
?? ?24+6x-24=63.6-24,
????????? 6x=39.6,
??? ?? 6x÷6=39.6÷6,
?????????? x=6.6;
⑥5x-7.2×5=12,
????? 5x-36=12,
?? 5x-36+36=12+36,
???????? 5x=48,
???? ?5x÷5=48÷5,
??????? ? x=9.6;
⑦3x+0.6x=28.8,
???? 3.6x=28.8,
3.6x÷3.6=28.8÷3.6,
??????? x=8;
?
? ⑧338-34x=42×4,
??? 338-34x=168,
338-34x+34x=168+34x,
??????? 338=168+34x,
??? 338-168=168+34x-168,
???????? 34x=170,
???? 34x÷34=170÷34,
?????????? x=5.
解析分析:①先化简,然后依据等式的性质,方程两边同时加7x,再同时减去23,最后再同时除以7求解;
②依据等式的性质,方程两边同时减去15,再同时除以5求解;
③先化简,再依据等式的性质,方程两边同时除以4求解.
④依据等式的性质,方程两边同时除以3,再同时减去9求解;
⑤先化简,然后依据等式的性质,方程两边同时减去24,再同时除以6求解;
⑥先化简,然后依据等式的性质,方程两边同时加上36,再同时除以5求解;
⑦先化简,然后依据等式的性质,方程两边同时除以3.6;
⑧依据等式的性质,方程两边同时加34x,再同时减去168,最后再同时除以34求解.
点评:等式的性质是解方程的依据,解答时注意对齐等号.