解方程
6x+4×(10-x)=48
4x+48=7x-15
(60+70)x=(50+70)×(x+2)
(x+20)×2=2.5x+20
x-10=[2×(x-10)-9]×5
3200x+6000×(6-x)=26200.
解方程6x+4×(10-x)=484x+48=7x-15(60+70)x=(50+70)×(x+2)(x+20)×2=2.5x+20x-10=[2×(x-10)-9]
答案:2 悬赏:40 手机版
解决时间 2021-01-04 01:29
- 提问者网友:不爱我么
- 2021-01-03 12:00
最佳答案
- 五星知识达人网友:傲气稳了全场
- 2021-01-03 13:03
解:(1)6x+4×(10-x)=48,
?????????????? 6x+40-4x=48,
?????????????? 2x+40-40=48-40,
???????????????????? 2x=8,
????????????????? 2x÷2=8÷2,
????????????????????? x=4;
(2)4x+48=7x-15,
? 4x+48+15=7x-15+15,
? 4x+63-4x=7x-4x,
??????? 63=3x,
???? 63÷3=3x÷3,
???????? x=21;
(3)(60+70)x=(50+70)×(x+2),
?????????? 130x=120x+240,
????? 130x-120x=120x+240-120x,
??????????? 10x=240,
??????? 10x÷10=240÷10,
????????????? x=24;
(4)(x+20)×2=2.5x+20,
?????????? 2x+40=2.5x+20,
??????? 2x+40-2x=2.5x+20-2x,
?????????? 40-20=20+0.5x-20,
????????????? 20=0.5x,
???????? 20÷0.5=0.5x÷0.5,
?????????????? x=40;
(5)x-10=[2×(x-10)-9]×5,
???? x-10=[2x-20-9]×5,
???? x-10=10x-145,
?x-10+145=10x-145+145,
? x+135-x=10x-x,
????? 135=9x,
???135÷9=9x÷9,
??????? x=15;
(6)3200x+6000×(6-x)=26200,
?????? 3200x+36000-6000x=26200,
???????????? 36000-2800x=26200,
???????36000-2800x+2800x=26200+2800x,
???????????? 36000-26200=26200+2800x-26200,
??????????????????? 9800=2800x,
????????????? 9800÷2800=2800x÷2800,
?????????????????????? x=3.5.解析分析:(1)先化简方程,再依据等式的性质,方程两边同时减40,再同时除以2求解,(2)依据等式的性质,方程两边同时减4x,再同时加15,最后同时除以3求解,(3)先化简方程,再依据等式的性质,方程两边同时减120x,最后同时除以10求解,(4)先化简方程,再依据等式的性质,方程两边同时减2x,然后同时减20,最后同时除以0.5求解,(5)先化简方程,再依据等式的性质,方程两边同时加145,,然后同时减x,最后同时除以9求解,(6)先化简方程,再依据等式的性质,方程两边同时加2800x,然后同时减26200,最后同时除以2800求解.点评:解方程的依据是等式的性质,对于能化简的要依据等式的性质先化简,解答时注意对齐等号.
?????????????? 6x+40-4x=48,
?????????????? 2x+40-40=48-40,
???????????????????? 2x=8,
????????????????? 2x÷2=8÷2,
????????????????????? x=4;
(2)4x+48=7x-15,
? 4x+48+15=7x-15+15,
? 4x+63-4x=7x-4x,
??????? 63=3x,
???? 63÷3=3x÷3,
???????? x=21;
(3)(60+70)x=(50+70)×(x+2),
?????????? 130x=120x+240,
????? 130x-120x=120x+240-120x,
??????????? 10x=240,
??????? 10x÷10=240÷10,
????????????? x=24;
(4)(x+20)×2=2.5x+20,
?????????? 2x+40=2.5x+20,
??????? 2x+40-2x=2.5x+20-2x,
?????????? 40-20=20+0.5x-20,
????????????? 20=0.5x,
???????? 20÷0.5=0.5x÷0.5,
?????????????? x=40;
(5)x-10=[2×(x-10)-9]×5,
???? x-10=[2x-20-9]×5,
???? x-10=10x-145,
?x-10+145=10x-145+145,
? x+135-x=10x-x,
????? 135=9x,
???135÷9=9x÷9,
??????? x=15;
(6)3200x+6000×(6-x)=26200,
?????? 3200x+36000-6000x=26200,
???????????? 36000-2800x=26200,
???????36000-2800x+2800x=26200+2800x,
???????????? 36000-26200=26200+2800x-26200,
??????????????????? 9800=2800x,
????????????? 9800÷2800=2800x÷2800,
?????????????????????? x=3.5.解析分析:(1)先化简方程,再依据等式的性质,方程两边同时减40,再同时除以2求解,(2)依据等式的性质,方程两边同时减4x,再同时加15,最后同时除以3求解,(3)先化简方程,再依据等式的性质,方程两边同时减120x,最后同时除以10求解,(4)先化简方程,再依据等式的性质,方程两边同时减2x,然后同时减20,最后同时除以0.5求解,(5)先化简方程,再依据等式的性质,方程两边同时加145,,然后同时减x,最后同时除以9求解,(6)先化简方程,再依据等式的性质,方程两边同时加2800x,然后同时减26200,最后同时除以2800求解.点评:解方程的依据是等式的性质,对于能化简的要依据等式的性质先化简,解答时注意对齐等号.
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- 1楼网友:我住北渡口
- 2021-01-03 14:00
感谢回答,我学习了
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