数学天才请进来

1.1/3x-2/7x=10
7x-6x=210
x=210
2. 40%x-25%x=75
40x-25x=7500
15x=7500
x=500
3. 6/17x23+23/1×17/9
=6/17*23+23*9/17
=23*(6/17+9/17)
=23*15/17
=345/17
4. 3.75×4.8+62.5×0.48
=3.75*4.8+6.25*4.8
=4.8*(3.75+6.25)
=4.8*10
=48

1/3X-2/7X=10 40%X-25%X=75
解: 1/21X=10 解:15%X=75
X=210 X=500
3.75×4.8+62.5×0.48
=(3.75+6.25)X4.8
=10X4.8
=48
抱歉,6/17+23+23/1×17/9没看明白

1/3x-2/7x=10；这个X=210
40%x-25%x=75；X=500
3.75×4.8+62.5×0.48=48
6/17+23+23/1×17/9=10220/153