1/3(2а-9)-1/2(5b+4)=2/3a-3-2 1/2b+2=
=2/3a-2 1/2b+2-3=2/3a-2 1/2b-1=
=2/3×4 1/2- 5/2×1/15-1=2/3×5/2-1/6-1=
=5/3-1/6-1=10/6-1/6-1=
=9/6-1=1 3/6-1=3/6=1/2
1/3(2а-9)-1/2(5b+4)=2/3a-3-2 1/2b+2=
=2/3a-2 1/2b+2-3=2/3a-2 1/2b-1=
=2/3×4 1/2- 5/2×1/15-1=2/3×5/2-1/6-1=
=5/3-1/6-1=10/6-1/6-1=
=9/6-1=1 3/6-1=3/6=1/2