Zad 4
a).-4(2x+0,5) = -8x-2
b).2/3(6y-15) = 4y-10
c).3(x²-2)-(5-6x²) = 3x²-6-5+6x² = 9x²-11
d).-3(1-2y)+1/2(6-12y) = -3+6y+3-6y = 0
e).-(x-2)-4(1/2 -x) = -x+2-2+4x = 3x
f).1-3(1/2 x -2)-1/2(1-3x) = 1 - 3/2 x +6 - 1/2 + 3/2 x = 7 - 1/2 = 6 i 1/2
Zad 5
a) (x + 1) (x + 4)=x^2+4x+x+4=x^2+5x+4
b) 2(2x +3) (2x - 1)=(4x+6)(2x-1)=8x^2-4x+12x-6=8x^2+8x-6
c) - (x + 7) (x - 3)=-(x^2-3x+7x-21)=-x^2+3x-7x+21=-x^2-4x+21
d) 1 - (z +5) (z - 1)=1-(z^2-z+5z-5)=1-z^2+z-5z+5=-z^2-4z+6
e)2k^2 - (k +3) (2k +4)=2k^2-(2k^2+4k+6k+12)=2k^2-2k^2-4k-6k-12=-10k-12
f) -3(a + 2b) (a - b) + 3a^2=-3(a^2-ab+2ab-2b^2)+3a^2=-3a^2+3ab-6ab+6b^2+3a^2=6b^2-3ab
