) 2a +[ 4a -( 3a +b)]

2) 3x -[ 5x +3y -( 2x -y)]

3) 2m +[ (5m -6n) - ( 2m +n)]
4) 4x2 +[-(3x
2
-5xy) + (-3y2 +5xy) - ( -3x2 +y2
)]

5) 6a +{ (-2a +b) - ( -a +b -c) +3a}

6) 4m -[ 2m +(4n -3)] +[ -4n -( 2m +1)]
7) 2x +[ -5x -2y + ( -x + y)]
8) 5x
2
-{ -7xy +[ -y
2 +( -x
2 +3xy -3y
2
] }
9) –4a +b + {3a +b - [-2a +b -( a -b) ] } +8a
10) -x +y - { x + y + [ -x –y - (x +y)]}