execution: 1. a) 4x^2-8xy= 4x(x-2y)
b) 4x^2-9y^2=(2x-3y)(2x+3y)
c) 3x^2+18x+27=3(x+3)^2
d) 3a(a-b)-a+b=3a(a-b)-(a-b)=(a-b)(3a-1)
e) x^4-x^2=x^2(x-1)(x+1)
f) 4-a^2+2ab-1=4-(a-b)^2
2. ...=(x-2)(x+2)(y-1)/(y(x+2)-(x+2)) = (x-2)(x+2)(y-1)/(x+2)(y-1) = x-2
3. a) x^2+3x=0
x(x+3)=0 => x=0 ili x+3=0, tj x=-3
b) (1+x)^2-4=0
x^2+2x-3=0 => x1=-3, x2=1;
4. a)... = (10+1/4)/(5/4+4+9/4)= 41/30
b) ...=4/(1/8*1/8 ):16/(2^4/2^5) =4*64/2*16=8
5. ...((y^3/x^2)/4)^(-2 )*(16/(1/xy^2))^(-1)*y^8/x^3= 16x^4/y^6 * 1/16xy^2 * y^8/x^3 = 1
hmm... to bi bilo to... aaako se i ja ne zeznuh negdje