1:C2:D3:D4:D5:4b 负六分之五M二次方N二次方6：-a +b-c7:2x²-x+18:-3/19:-ab（7次方）10:11y-9 2a -x-1 -32x-11 -13x²+10x-1 a²+5a+411:B12:B13:4514:15XY-6X-9 Y=0.416:-2A²-ab+17b²17:a-...