Question

数学计算题！急急急！

用简便方法计算！
1.25×7×8 17÷0.25÷3.4 6.3÷0.8＋2.125

103×4.7 3.4×2.5÷0.5

方程式解答！

8×（x-61.2）=40.8 6×9-3x=18 4x+（11.3-5.3）x=12.8

3.2x+1.8x=10.5 34.34÷2x=1.7 25.74÷3x=3

O(∩_∩)O谢谢了

Answer 1

1.25×7×8 17÷0.25÷3.4 6.3÷0.8＋2.125

=1.25×8×7 =17÷3.4 ÷0.25 正常运算
=10×7 =5÷0.25
=70 =20
103×4.7 3.4×2.5÷0.5
=(100+3)×4.7 =3.4×5
=100×4.7 +3×4.7 =17
=400+14.1
=414.1
方程式解答！

8×（x-61.2）=40.8 6×9-3x=18 4x+（11.3-5.3）x=12.8
X=66.3 X=12 10 X=12.8
X=1.28

3.2x+1.8x=10.5 34.34÷2x=1.7 25.74÷3x=3

5X=10.5 2X=20.2 3X=8.58
X=2.1 X=10.1 X=2.86

Answer 2

1.25×7×8
=1.25×8×7
=10×7
=70
17÷0.25÷3.4
=17÷3.4×4
=5×4
=20
6.3÷0.8＋2.125
这个是不是写错了？是6.3÷0.8÷0.125吧？
6.3÷0.8÷0.125
=6.3÷（0.8×0.125）
=6.3÷0.1
=63
103×4.7
=(100+3)×4.7
=100×4.7 +3×4.7
=470+14.1
=484.1

3.4×2.5÷0.5
=3.4×2.5×2
=3.4×5
=17
方程式解答！

8×（x-61.2）=40.8
x=40.8÷8+61.2
=5.1+61.2
=66.3

6×9-3x=18
x=(6×9-18)÷3
=36÷3
=12

4x+（11.3-5.3）x=12.8
10x=12.8
x=1.28

3.2x+1.8x=10.5
5x=10.5
x=10.5÷5=2.1
34.34÷2x=1.7
x=34.34÷1.7÷2
=34.34÷3.4
=10.1

25.74÷3x=3
x=25.74÷3÷3
=25.74÷9
=2.86

Answer 3

1.25×7×8 17÷0.25÷3.4 6.3÷0.8＋2.125
=1.25×8×7 =17÷3.4÷0.25 没有简便计算
=10×7 =5÷0.25
=70 =20
103×4.7 3.4×2.5÷0.5
=（100+3）×4.7 =3.4×(2.5÷0.5）
=100×4.7+3×4.7 =3.4×5
=470+14.1 =17
=484.1
方程式解答！

8×（x-61.2）=40.8
x=40.8÷8+61.2
=5.1+61.2
=66.3

6×9-3x=18
x=(6×9-18)÷3
=36÷3
=12

4x+（11.3-5.3）x=12.8
10x=12.8
x=1.28

3.2x+1.8x=10.5
5x=10.5
x=10.5÷5=2.1
34.34÷2x=1.7
x=34.34÷1.7÷2
x=34.34÷3.4
x=10.1

25.74÷3x=3
x=25.74÷3÷3
x=25.74÷9
x=2.86

Answer 4

太简单了，但太多勒。又没分…不做

Answer 5

1.25×7×8=（1.25×8）×7=10×7=70
17÷0.25÷3.4=17×4÷3.4=68÷3.4=20