题目内容
解方程.
6.2x-2x=8.4
3.6×5-0.5x=8.5
3.6+5.4x=27
2.96+5x=0.8.
6.2x-2x=8.4
3.6×5-0.5x=8.5
3.6+5.4x=27
2.96+5x=0.8.
分析:(1)先化简方程,再依据等式的性质,方程两边同时除以4.2求解,
(2)先化简方程,再依据等式的性质,方程两边同时加0.5x,然后同时减8.5,最后同时除以0.5求解,
(3)依据等式的性质,方程两边同时减3.6,再同时除以5.4求解,
(4)依据等式的性质,方程两边同时减2.96,再同时除以5求解.
(2)先化简方程,再依据等式的性质,方程两边同时加0.5x,然后同时减8.5,最后同时除以0.5求解,
(3)依据等式的性质,方程两边同时减3.6,再同时除以5.4求解,
(4)依据等式的性质,方程两边同时减2.96,再同时除以5求解.
解答:解:(1)6.2x-2x=8.4
4.2x=8.4
4.2x÷4.2=8.4÷4.2
x=2;
(2)3.6×5-0.5x=8.5
18-0.5x+0.5x=8.5+0.5x
18-8.5=8.5+0.5x-8.5
9.5÷0.5=0.5x÷0.5
x=19;
(3)3.6+5.4x=27
3.6+5.4x-3.6=27-3.6
5.4x÷5.4=23.4÷5.4
x=4
;
(4)2.96+5x=0.8
2.96+5x-2.96=0.8-2.96
5x÷5=-2.16÷5
x=-0.432.
4.2x=8.4
4.2x÷4.2=8.4÷4.2
x=2;
(2)3.6×5-0.5x=8.5
18-0.5x+0.5x=8.5+0.5x
18-8.5=8.5+0.5x-8.5
9.5÷0.5=0.5x÷0.5
x=19;
(3)3.6+5.4x=27
3.6+5.4x-3.6=27-3.6
5.4x÷5.4=23.4÷5.4
x=4
1 |
3 |
(4)2.96+5x=0.8
2.96+5x-2.96=0.8-2.96
5x÷5=-2.16÷5
x=-0.432.
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.
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