1.5х(х+4)-х(7-0.5х)=0.5(10-2х)=
=1.5х+6х-7х+0.5х=5-х
=1.5х+6х-7х+0.5х+х=5
х=5
2/5 - /5 * /9 + /16 * /5 = 2/5 - 3/5 + 4/5 = 3/5