1)
2)

1)   5/12·2²/₃-7²/₃·(-1/6)=5/12·8/3-23/3·(1/6)=(5·8)/(12·3)+8/(3·6)=
=10/9+4/9=(10+4)/9=14/9=1⁵/₉;
2)   -1³/₇·4²/₃+1⁷/₉·(-4/3)=-10/7·14/3+16/9·(-4/3)=-(14·10)/(7·3)-(16·4)/(9·3)=
=-20/3-64/27=(-180-64)27=-244/27=-9¹/₂₇;