Bonsoir,
A:B/D:G/I:J/H:C:E:F.
A:B car a:4+2+x²=6x²=B.
D:G car d=2×4+x²=8x²=G.
H:C:E:F car h:x+x+x+x+x+x=7x-x=4+2+x=6x=C=E=F.