Répondre :
1) (8x+7)2 -2(x+3)(8x+7)=
= 64x2 +8x*2*7+49 - 2( 8x2+ 7x+ 24x+21=
= 64x2+112x+48-2(8x2+31x+21)=
=64x2+112x+48-16x2-62x-42=
=48x2+50x+6
2)
= 64x2 +8x*2*7+49 - 2( 8x2+ 7x+ 24x+21=
= 64x2+112x+48-2(8x2+31x+21)=
=64x2+112x+48-16x2-62x-42=
=48x2+50x+6
2)