1. (√3-2) (√3+2)= √9 + 2√3 -2√3 +4= 3+4=7
2.(A^2+0,5)^2=a^4+0,5^2=a^4+0,25
3. (2-4x)^2= (2-4x)(2-4x)= 4-8x-8x+16x^2= 4+18x^2
4. (x+1) (x-1) + (2x-4)^= x^2-x+x-1+4+18x^2=x^2+18x^2+3= 3+19x^2
5. 3(a-1)2-2(3a+1)2= 3 [ (a-1)(a-1)] -2 [(3a+1)(3a+1)]=
= 3 [a^2-a-a+1]-2[9a^2+3a+3a+1]=
= 3 [a^2-2a+1]-2[ 9a^2+6a+1]
= 3a^2-6a+3 -18a^2-12a-2=
= -15a^2-18a+1