Bonjour,
1)A=(2x+1)*3x-(2x+1)*2+2*2x-2*1
=3x*2x+3x*1-2*2x+2*1+4x-2
=6x^2+3x-4x+2+8x
=6x^2+12x^2+2+8x
=18x^2+2+8x
2)A=(2*3+1)(3*3-2)+(2*3-1)2
=(2*3+1)*3*(2*3+1)*3-(2*3+1)*2+2*2*2*3-2*1
=3*2*3*3+3*1*3*2*3*3+3*1-2*2*2*3+2*1+4*6-2
=6*9+3*6*9+3-4*6+2+24-2
=54+18*9+3-24+26-2
=54+162+21+24
=216+45
=261