(1,2x-0,5) (7x-1) <0

8,4х²-1,2х-3,5х+0,5∠0
8,4х²-4,7х+0,5∠0
д=22,09-16,8=5,29
  х4,7-2,3/16,8=2.4/16,8=7
х=4,7+2.3/16,8=6.9/16,8=