1)=a^2+8a+16
2)=9y^2-6yc+c^2
3)=4a^2-25
4)=x^4-y^2
(х - 3)² = 9х - х²+2
log√2(7√2)-log√2(14)= log√2(7√2/14)= log√2(√2/2)= log√2(1/√2)= -1