a) =21x-3-21x+7=4
b) =5x-1-3(5x-3):3=se simplif impartirea cu 3=5x-1-5x+3=2
c) =12x²-9-12x²+16=7
d) =20x²-16+15x-12-20x²+10x+12=25x-16
e) =4(2x-1):4-3(4x-1):3=2x-1-4x+1=-2x
f) =24x²+20x-12x-10-24x²+80x-3x+10=85x
g) =-9x+10-2{7x-3(-31+31x)]
=-9x+10-2(7x+93-93x)
=-9x+10-14x-186+186x
=163x-176