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X^2-×-6=?
(X^2 inseamna x la puterea a 2 a)


Răspuns :

[tex]x^{2} - x - 6 = \\ {x}^{2} + 2x - 3x - 6 \\ x(x + 2) - 3(x + 2) \\( x + 2)(x - 3)[/tex]

Daca mai ai nevoie, stiind ca (x-3)(x+2) = 0
=> unul dintre factori este 0
pt x -3 = 0 => x =3
pt x+2 = 0 => x=-2
[tex] {x}^{2} - x - 6[/tex]

[tex] {x}^{2} - x - 6 = 0[/tex]

[tex]a = 1[/tex]

[tex]b = - 1[/tex]

[tex]c = - 6[/tex]

[tex]delta = {b}^{2} - 4ac[/tex]

[tex]delta = ( - {1})^{2} - 4 \times 1 \times ( - 6)[/tex]

[tex]delta = 1 + 24[/tex]

[tex]delta = 25 > 0 [/tex]

[tex] = > exista \: x1 \: diferit \: de \: x2[/tex]

[tex]x1.2 = \frac{ - b + - \sqrt{delta} }{2a} [/tex]

[tex]x1.2 = \frac{ - ( - 1) + - \sqrt{25} }{2 \times 1} [/tex]

[tex]x1.2 = \frac{1 + - 5} {2} [/tex]

[tex]x1 = \frac{1 + 5}{2} [/tex]

[tex]x1 = \frac{6}{2} [/tex]

[tex]x1 = 3[/tex]

[tex]x2 = \frac{1 - 5}{2} [/tex]

[tex]x2 = - \frac{4}{2} [/tex]

[tex]x2 = - 2[/tex]