11)
[tex] {x}^{2} - 4x + 4 = \\ = {x}^{2} - 2x - 2x + 4 = \\ = x(x - 2) - 2(x - 2) = \\ = (x - 2)(x - 2) = \\ = (x - 2) {}^{2} = \color{green}patrat \: perfect[/tex]
12)
[tex] \color{red} {(a + b)}^{3} = {a}^{3} + 3a {}^{2}b + 3ab {}^{2} + b {}^{3} [/tex]
[tex](x + 2) {}^{3} = x {}^{3} + 6 {x}^{2} + 12x + 8[/tex]
[tex] \color{red} {(a - b)}^{3} = {a}^{3} - 3a {}^{2}b + 3ab {}^{2} - b {}^{3} [/tex]
[tex](x - 2) {}^{3} = x {}^{3} - 6x {}^{2} + 12x - 8 [/tex]
[tex](x + 2) {}^{3} + ( {x - 2)}^{2} = \\ = (x {}^{3} + 6x {}^{2} + 12x + 8) + (x {}^{3} - 6x {}^{2} + 12x - 8) = \\ = 2x {}^{3} + 24x = 2x(x {}^{2} + 12)[/tex]
(daca nu vezi tot glisează spre stânga )
13)
probabilitatea = Nr cazuri favorabile / Nr cazuri posibile
Nr cazuri posibile = 4 +6+8=18
nr cazuri favorabile = 8
probabilitatea= 8/18 simplificam prin 2=2/9
…ᘛ⁐̤ᕐᐷฅ^•ﻌ•^ฅฅ^•ﻌ•^ฅ
