题目内容
(2009?江安县模拟)解方程.
4÷
X=
x-1.4+1.6=3
:18%=
.
4÷
2 |
3 |
2 |
5 |
x-1.4+1.6=3
3 |
20 |
6.5 |
x |
分析:(1)先把除法转化为乘法,化简得6X=
,再根据等式的性质,两边同除以6即可;
(2)运用加法交换律,把原式变为x+(1.6-1.4)=3,即x+0.2=3,再根据等式的性质,两边同减去0.2即可;
(3)先化简等式左边,再把原式改写成5:6=6.5:x,根据比例的性质得5x=6×6.5,再根据等式的性质,两边同除以5即可.
2 |
5 |
(2)运用加法交换律,把原式变为x+(1.6-1.4)=3,即x+0.2=3,再根据等式的性质,两边同减去0.2即可;
(3)先化简等式左边,再把原式改写成5:6=6.5:x,根据比例的性质得5x=6×6.5,再根据等式的性质,两边同除以5即可.
解答:解:(1)4÷
X=
,
4×
X=
,
6X=
,
6X÷6=
÷6,
X=
×
,
X=
;
(2)x-1.4+1.6=3,
x+(1.6-1.4)=3,
x+0.2=3,
x+0.2-0.2=3-0.2,
x=2.8;
(3)
:18%=
,
5:6=6.5:x,
5x=6×6.5,
5x=39,
5x÷5=39÷5,
x=
.
2 |
3 |
2 |
5 |
4×
3 |
2 |
2 |
5 |
6X=
2 |
5 |
6X÷6=
2 |
5 |
X=
2 |
5 |
1 |
6 |
X=
1 |
15 |
(2)x-1.4+1.6=3,
x+(1.6-1.4)=3,
x+0.2=3,
x+0.2-0.2=3-0.2,
x=2.8;
(3)
3 |
20 |
6.5 |
x |
5:6=6.5:x,
5x=6×6.5,
5x=39,
5x÷5=39÷5,
x=
39 |
5 |
点评:此题考查了根据等式的性质解方程,即方程两边同加、同减、同乘或同除以某数(0除外),方程的左右两边仍相等;注意“=”号上下要对齐.
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