1) а) С2-3с+2с-6-с2-3с-1с-3=-5с-9;
<span>б) 16х2-24х+9-24х+6х2=22х2-48х+9;</span>
<span>в) в2-9+4в2+12в+9=5в2+12в</span>
000000000000000000000000000000000000
<span>{x+2y=6
{x-3y=-14
х=6-2у
6-2у-3у=-14
х=6-2у
-5у=-20
х=6-2у
у=4
х=-2
у=4
(-2; 4)</span>
.......=(25а^2-20a+4-4b^2)=
=(25a^2-20a)+(4-4b^2)=
=(4-20a)+(25a-4)