1) (a+2b+1)\(^2\)
=a\(^2\)+2a(2b+1)+(2b+1)2
=a2+4ab+2a+(2b)2+2.2b.1+12
=a2+4ab+2a+4b2+4b+1
2) (2a-b+3)2
=(2a)2 -2.2a(b-3)+(b-3)2
=4a2-4a(b-3)+b2-2b.3+32
=4a2-4ab+12a+b2 -6b+9
3) (2a-3b+1)2
=(2a)2-2.2a(3b-1)+(3b-1)2
=4a2-4a(3b-1)+(3b)2-2.3b.1+12
=4a2-4ab+4a+9b2-6b+1