12/7*(√0,1(6) - 5/√6 +1/2√6)=
= 12/7 * ( √(16-1)/90 - 5/√6 + 1/2√6)=
=12/7 * ( √15/90 - 5√6/6 + √6/2*6) =
= 12/7 * ( √15/90 - 10√6/12+ √6/12)=
= 12/7 * (√15/90 - 9√6/12)
= 12/7 * ( √1/6 - 9√6/12)
= 12/7* ( 1/√6 - 9√6/12)
= 12/7 * ( √6/6 - 9√6/12)
=12/7 * ( 2√6/12-9√6/12)
=12/7 * ( -7√6/12)
=-√6