1. a) (x+4)^2=x^2+8x+16
b) (x-3)^2=x^2-6x+9
2. 8x^7+12x^3=
4x^4(2x^4+3)
b) x^2-49= (x-7)×(x+7)
3. 5x^2=245
x^2=49
x=7
4. x=2+2rad.3+3+1-6
x=2rad.3
2rad.3<5
5. E(x)=3x^5-6x^4+3x^3
E(x)=3x^3×(x^2-2x+1)
E(x)=3x^3×(x-1)^2
6. 10a+b-a^2-b<25
10a-a^2<25
