A .3(3x+2y-6)-5 (4x-3y -2 ) + 7 ( 3x-5 y -1 ) =
=9x+6y-18-20x+15y+10 + 21x-35y -7 =
=10x-14y-15
B . 4(2a-3b+4c) +2 (3a +2b-3c) - 3( a - 2b + 2c ) =
=8a-12b+16c +6a +4b-6c - 3a +6b -6c =
=11a-2b+4c
C . 6 (a-2b + c ) - 3 (2a-4b+c ) + 5 (-a +3b -2c)
=
=6a-12b +6c -6a+12b-3c -5a +15b -10c
=
= -5a +15b -7c