480\х - 480\ х+4 = 4
480 *( х+4) - 480х = 4х *( х+4)
480х + 1920 - 480х = 4х^2 + 16х
- 4х^2 - 16х + 1920 = 0
4х^2 + 16х - 1920 =0
Д = 256 - 4 * 4 *( - 1920) = 256 + 30 720 = 30 976 = 176
х1 = -256 + 176 \ 8 = - 80 \ 8 = - 10
х2 = - 256 - 176 \ 8 = - 432\8 = - 54