1a. (169+26y+y^2)
б. (9y^2-24y+16)
в. (9y^2-4x^2)
г. (x^2-4x^4)
2. a. (17-x)(17+x)
б. (4y-3x)*(4y-3х)
в. (7x-(x-3))*(7x+(x-3))=(6x+3)*(8x-3)
3. (a^2-4ab+4b^2)+4ab-4b^2=a^2-4ab+4b^2+4ab-4b^2=a^2. При а=-2/3, а^2=4/9
5 б. 25x^2-49=0
25X^2=49
x^2=49/25
х=+- 7/5