Question

multimea solutiilor ecuatiei x²+x-6=0 este {...} URGENT VA ROG FRUMOS!!

Answer 1

X poate fi doar 2 deoarece

2²+2-6=4+2-6=6-6=0

Answer 2

x²+x-6=0 ⇔ x² + 3x - 2x - 6 = 0 ⇔ x(x+3) -2(x+3) =0 ⇔ (x+3)(x-2)=0

x+3=0 ⇒ x = -3

x-2=0 ⇒ x=2

Deci, ecuatia admite doua solutii : x = -3   si   x = 2.


$\it Sau:$

$\it x^2+x-6 =0,\ a=1,\ b=1,\ c=-6$

$\it\Delta =b^2-4ac =1^2-4\cdot1\cdot(-6) = 1+24=25$

$\it x_{1,2} =\dfrac {-b \pm \sqrt{\Delta}}{2a} =\dfrac{-1\pm\sqrt{25}}{2\cdot1} =\dfrac{-1\pm5}{2}$

[tex]\begin{cases}\it x_1=\dfrac{-1-5}{2}=\dfrac{-6}{2}=-3 \\\;\\ \it x_2 = \dfrac{-1+5}{2}=\dfrac{4}{2}=2\end{cases}[/tex]