给我一步一步解方程!一部一部!
问题描述：
给我一步一步解方程!一部一部!
5%x-5%x*4/5=20
2x=（280+x）2/7+280
7/9x=5/6(x-3)
2/3x-21=3/8x
答
5%x-5%x*4/5=205%x-4%x =201%x =20x = 20002x=（280+x）2/7+2802x = 80 + (2/7)x +280(12/7)x =360x = 2107/9x=5/6(x-3)42x =45(x-3)42x =45x - 1353x = 135x =452/3x-21=3/8x 16x - 504 = 9x7x =504x =72