решите (6+b)×(6+b)
(t+m)²
(t-3)²
(2t+1)²

(6+b)×(6+b)=(6+b)²=36+12b+b².
==========================================================
(t+m)²=t²+2tm+m²=t²+2mt+m².
==========================================================
(t-3)²=t²-2t*3+3²=t²-6t+9.
==========================================================
(2t+1)²=(2t)²+2*3t*1+1²=4t²+4t+1.
==========================================================