1.2ax+ay+4bx+2by-6cx-3cy
=a(2x+y)+2b(2x+y)-3c(2x+y)
=(2x+y)(a+2b-3c)
2.a^2-4ab+4b^2-4
=(a-2b)^2-4
=(a-2b+2)(a-2b-2)
3.a^2-4ab+4b^2-2a+4b+1
=(a-2b)^2-2(a-2b)+1
=(a-2b-1)^2
1.2ax+ay+4bx+2by-6cx-3cy
=a(2x+y)+2b(2x+y)-3c(2x+y)
=(2x+y)(a+2b-3c)
2.a^2-4ab+4b^2-4
=(a-2b)^2-4
=(a-2b+2)(a-2b-2)
3.a^2-4ab+4b^2-2a+4b+1
=(a-2b)^2-2(a-2b)+1
=(a-2b-1)^2